JP2007190779A - Inkjet drawing method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet drawing method and an apparatus therefor whereby an image of high positional accuracy can be formed. <P>SOLUTION: Photo-curing type ink is ejected as ink liquid droplets by an inkjet head 14 and directly drawn in the form of the image on an image recording medium. At a rear position separated by a predetermined distance from a drawing position by the inkjet head 14 to the downstream side of sub scanning conveyance of the image recording medium, an active light from a still dot-like or nearly dot-like active light light source is shed onto the image recording medium by a scanning mirror which moves scanning in a main scanning direction. The photo-curing type ink ejected in the form of the image onto the image recording medium is thus cured, whereby the image is formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet drawing method and apparatus for recording an image on a sheet-like image recording medium by an ink jet recording method, and more particularly, to an ink jet printing plate used for a plate making apparatus for producing a printing plate for lithographic printing. The present invention relates to an inkjet drawing method and apparatus for forming an image by a recording method.

  In lithographic printing, printing ink receptivity (ink repellency) and printing ink repulsion (ink repellency) areas are provided on the surface of the printing plate corresponding to the image original, and the printing ink is attached to the ink receptivity areas. Print. Normally, hydrophilic (ink repellency) and oleophilic (ink receptivity or ink repellency) areas are formed on the surface of the printing plate in an image-like manner, and the hydrophilic areas are ink-repellent using dampening water ( Ink repellency).

  Conventionally, an original including an image is separated into colors of, for example, C (cyan), M (magenta), Y (yellow), and K (black) for a color original as it is for a black and white original. For each color, the silver salt photographic film (lith film) is once exposed and developed in an analog or digital manner, and a film plate is output. Using this film plate, a diazo resin or a photopolymerizable photopolymer photosensitive material ( A printing plate on which an image is formed is made (plate making) for each color by exposing to a printing original plate) and, for example, eluting and removing a non-image portion mainly using an alkaline solution.

  In recent years, many systems for directly drawing digital image information on a printing original plate have been proposed in order to improve digital drawing technology and increase process efficiency. As an example of a system that directly draws such digital image information on a printing original plate, there is known a system that records an image on a photosensitive layer or a heat-sensitive layer of a printing original plate in a light mode or a thermal mode using a laser. Yes. However, in this plate making method, in both the optical mode and the heat mode, generally, a printing original plate (such as a photosensitive layer or a heat sensitive layer) exposed with an alkaline developer after laser recording is processed to dissolve and remove the non-image area. Therefore, if the alkaline waste liquid is discharged as it is, it is not preferable for environmental conservation, and the treatment of the alkaline waste liquid is required. Further, the method using a laser is expensive and large.

  In order to solve such problems, an attempt has been made to apply an inkjet recording method, which is an inexpensive and compact drawing method. By forming the image directly on the printing original plate by the ink jet recording method, the printing plate can be produced without dissolving and removing the non-image portion. Further, the device can be miniaturized.

  As a recording apparatus using an ink jet recording method, Patent Documents 1 and 2 disclose an ink jet printer using UV ink, which ejects ultraviolet (UV) curable ink (hereinafter referred to as UV ink) from an ink jet head as ink droplets. It is disclosed. In such an inkjet printer using UV ink, the UV irradiation means for irradiating the UV ink droplet ejected from the inkjet head and landing on the surface of the print medium with ultraviolet rays to cure the UV ink droplet is an inkjet head. It is provided beside. In this way, immediately after the UV ink is landed as droplets on the surface of the print media, the UV ink droplets are irradiated with ultraviolet rays by the UV irradiation means, and the UV ink is quickly dried and cured. An image is formed.

Here, since the inkjet printer disclosed in Patent Document 1 has a built-in UV lamp that emits high heat as the UV irradiation means, UV emitted from the UV lamp of the UV irradiation means at the standby position of the inkjet head and the UV irradiation means. In order to prevent the printer portion irradiated with light from being heated to a high temperature, cooling means for cooling the cover that is irradiated with UV light emitted from the window on the lower surface of the UV irradiation means is provided.
On the other hand, the apparatus disclosed in Patent Document 2 uses a UVLED or a UVLED array as a UV irradiation unit, thereby consuming a large amount of power such as a high-pressure mercury lamp or a metal halide lamp, that is, a drawback of a UV lamp that generates high heat. Is eliminated, the energy consumption of the UV irradiation means is suppressed, and the size of the UV irradiation means is reduced. Patent Document 2 discloses a configuration example in which the inkjet head and the UV irradiation unit are moved together and a configuration example in which the inkjet head and the UV irradiation unit are moved separately.

JP 2004-322560 A JP 2004-358769 A

By the way, in a plate making apparatus using a printing original plate as a recording medium (print medium), when an ink jet printer in which UV irradiation means such as a UV lamp disclosed in Patent Document 1 is provided beside an ink jet head, drawing by the ink jet head is applied. In order to cure the UV ink immediately after drawing near the position, the UV lamp is irradiated with UV light containing a heat component, and receives heat from the high-temperature UV lamp. For this reason, the printing original plate irradiated with high-temperature UV light and receiving heat from the high-temperature UV lamp is deformed due to thermal expansion at the drawing (recording) position due to heating. There is a problem that image displacement occurs.
Further, the shift of the image forming position of the printing original plate is particularly problematic because the color shift occurs in the case of multicolor printing in which images are formed with a plurality of printing plates.

  On the other hand, when an inkjet printer using the UVLED or the UVLED array disclosed in Patent Document 2 as a UV irradiation unit is applied to a plate making apparatus, the energy consumption is reduced regardless of whether the inkjet head and the UV irradiation unit are integrated or separate. Since it is small, there is no problem of heat generation in the UVLED itself, and the apparatus configuration is downsized, but there is a problem that it is expensive.

  An object of the present invention is to solve the above-mentioned problems of the prior art, and can irradiate scanning light with no waste or loss of active light emitted from a low-cost or substantially point-like active light source, Even if the image recording medium such as a lithographic printing plate precursor is deformed due to thermal expansion by irradiation with actinic light containing a heat component or by receiving heat from a high-temperature actinic light source, the accuracy of the drawn image is improved. An object of the present invention is to provide an ink jet drawing method and apparatus capable of eliminating an influence and forming an image with high positional accuracy.

  In order to solve the above-mentioned problems, a first aspect of the present invention is an ink jet drawing apparatus for recording an image on a sheet-like image recording medium by an ink jet recording method, the supporting table for supporting the image recording medium, An inkjet head disposed opposite to a support base and ejecting photocurable ink as ink droplets imagewise onto the image recording medium placed on the support base, and the inkjet head in the main scanning direction A head moving mechanism for moving the image recording medium is disposed on the downstream side of the image recording medium so as to be opposed to the ink jet head so as to be opposed to the support base, and actinic rays are applied to the image recording medium. A scanning type active light irradiation unit that scans and irradiates in the scanning direction and cures the photocurable ink discharged onto the image recording medium, and the image recording medium A transport mechanism that transports relative to the inkjet head in a sub-scanning direction that is substantially orthogonal to the main scanning direction, and the scanning-type active light irradiation unit emits the active light in the form of dots or substantially dots -Shaped active light source, parallel light generating means for generating the active light emitted from the active light source as parallel light parallel to the recording surface of the image recording medium supported by the support, and the parallel light generation The parallel light generated by the means is reflected to the image recording medium side and has a scanning mirror that can move in the main scanning direction and a mirror moving mechanism that moves the scanning mirror in the main scanning direction. An ink jet drawing apparatus is provided.

Here, actinic rays are ultraviolet (UV) light, visible light, infrared light, etc. The photocurable ink is ink that cures when irradiated with actinic rays.
Further, it is preferable to use ultraviolet (UV) light for the actinic ray and ultraviolet curable ink (UV ink) for the photocurable ink.
The mirror moving mechanism includes two conveying rollers arranged on both outer sides of the image recording medium in the main scanning direction and the two conveying rollers, and the scanning mirror is inclined by a predetermined angle. An endless belt to be attached, and an irradiation window that is formed adjacent to the attachment position of the scanning mirror and transmits the irradiation light reflected by the scanning mirror in the belt portion of the endless belt on the image recording medium side Is preferred.

The scanning-type actinic light irradiation unit further includes two specular plates arranged on both sides of the endless belt in the sub-scanning direction and having mutually opposite inner portions as mirror surfaces, and the parallel light generating means Includes a reflector having an exit having the rectangular cross-sectional shape for emitting the active light emitted from the active light source as the parallel light having a rectangular cross-sectional shape, and the active light source and the reflector include the endless belt Between the two parallel belt portions and on the outer side of the image recording medium in the main scanning direction, the mutually opposite inner portions of the two parallel belt portions of the endless belt form a mirror surface, and the scanning mirror The two belt portions are attached to the inside of the belt portion on the support side at an inclination of the predetermined angle, and the irradiation window is provided by the scanning mirror of the belt portion on the support side. Parallel light having the rectangular cross-sectional shape that is formed at a position to transmit the emitted irradiation light and is emitted from the exit of the reflector between the two parallel belt portions of the endless belt and between the two mirror plates. It is preferable to form a waveguide having a rectangular cross section that guides the light.
Further, the endless belt is preferably a stainless steel belt in which inner portions of the two belt portions facing each other are mirror surfaces.

Further, an irradiation unit moving mechanism that moves the scanning-type active light irradiation unit relative to the inkjet head in the sub-scanning direction, and the scanning-type active light irradiation unit and the inkjet head are arranged at the predetermined distance. It is preferable to have the irradiation unit moving mechanism or the head moving mechanism and a control unit that controls the irradiation unit moving mechanism so as to be separated from each other.
The transport mechanism is preferably a mechanism that transports the image recording medium in the sub-scanning direction.
The transport mechanism is preferably a mechanism that places the inkjet head, the head moving mechanism, and the scanning-type actinic light irradiation unit and moves them in the sub-scanning direction as a unit.
The image recording medium on which the image is recorded is preferably a lithographic printing plate.
Further, it is preferable that the image recording medium is a lithographic printing original plate and further includes a plate surface protective liquid discharge head for discharging a plate surface protective liquid onto the printing original plate drawn by the inkjet head.

  In order to solve the above-described problem, a second aspect of the present invention is a method in which a photo ink is used by a serial type ink jet (print) head moving in the main scanning direction, and the sub-direction orthogonal to the main scanning direction is used. An ink jet drawing method for directly forming an image on a sheet-like image recording medium conveyed relatively in a scanning direction, wherein the photocurable ink is ejected imagewise as ink droplets by the ink jet head and directly drawn. The active light from a stationary point-like or substantially point-like active light source is scanned in the main scanning direction at a rear position spaced a predetermined distance from the drawing position by the inkjet head to the downstream side of the image recording medium in the sub-scanning direction. The photo-curing ink irradiated onto the image recording medium by the moving scanning mirror and ejected imagewise onto the image recording medium. By reduction, there is provided an inkjet drawing method characterized by forming said image.

In the first and second aspects, it is preferable that the predetermined distance is a distance at which the influence of heat from the active light source does not affect drawing by the inkjet head.
The predetermined distance includes the drawing speed by the inkjet head, the type or structure of the inkjet head and the active light source, the transport speed of the image recording medium relative to the inkjet head, and the image It is preferably determined according to at least one of the material or material of the recording medium and the amount of active light emitted from the active light source.

Moreover, it is preferable that the said control part changes the moving speed of the said scanning mirror based on the emitted light quantity of the said active light source.
Further, it is preferable that the control unit shifts the moving speed of the scanning mirror in multiple stages.
Further, it is preferable that the irradiation unit moving mechanism moves the active light source or the scanning active light irradiation unit at a speed different from a relative moving speed between the image recording medium and the inkjet head.

  The printing plate preferably has a hydrophilic layer and an ink receiving layer sequentially on an aluminum support having an anodized layer.

  According to the first and second aspects of the present invention, the active light emitted from the stationary active light source at the rear position separated by a predetermined distance from the drawing position by the inkjet head to the downstream side of the sub-scanning conveyance of the image recording medium. Light-curing ink ejected imagewise on the image recording medium by a scanning mirror that moves in the main scanning direction is irradiated and cured to form an image. The lithographic printing plate can irradiate scanning light with active light emitted from a light source without waste or loss, and can be irradiated with active light containing a heat component or receive heat from a high-heat active light source. Even if deformation due to thermal expansion occurs in an image recording medium such as an original plate, it is possible to eliminate the influence on the accuracy of the drawn image and form a high-quality and high-accuracy image with high positional accuracy.

Further, according to the present invention, the actinic light source can be kept stationary, so that the photocurable ink can be quickly produced even when using a low-cost low-vibration point-like or substantially point-like ultraviolet light source. Can be dried and cured. For example, even if using a low-cost point light source such as an ultra-high pressure mercury lamp (lamp), the electrode bends when it vibrates, or the arc position shifts and the bulb (bulb) easily breaks. A photo-curable ink such as ink can be quickly dried and cured.
Further, in the case where the actinic light source or the scanning type actinic light irradiation unit is moved in the sub scanning direction with respect to the ink jet head, the drawing position by the ink jet head and the scanning light irradiation position of the actinic light by the scanning mirror in the sub scanning direction. Since the predetermined distance can be adjusted, the irradiation time of the active light (light beam) to the image recording medium such as the printing original plate can be adjusted, and the photocurable ink on the printing original plate can be suitably cured. .

  DETAILED DESCRIPTION OF THE INVENTION An ink jet drawing method and apparatus according to the present invention will be described below in detail based on preferred embodiments shown in the accompanying drawings.

FIG. 1 is a schematic top view showing a schematic configuration of an embodiment of a plate making apparatus to which the ink jet drawing apparatus according to the first aspect of the present invention for carrying out the ink jet drawing method according to the second aspect of the present invention is applied. 2 is a schematic cross-sectional view of the plate-making apparatus shown in FIG. 1, and FIGS. 3A and 3B are schematic cross-sections of the scanning UV irradiation unit of the plate-making apparatus shown in FIG. 1, respectively. It is a figure and a typical fragmentary sectional view.
In the following, a lithographic printing original plate as an image recording medium, an ultraviolet ray curable ink (hereinafter referred to as UV ink) as a photocurable ink, ultraviolet light (line) (hereinafter referred to as UV light) as active light, a dot shape or an approximately A plate making apparatus for producing a printing plate using an ultraviolet lamp (hereinafter referred to as a UV lamp) as a spot-like active light source will be described as a representative example, but it goes without saying that the present invention is not limited to this.

  The plate making apparatus 10 shown in FIG. 1 and FIG. 2 applies an ink jet drawing apparatus that forms a printing ink receptive (ink affinity) image portion on a recording surface of a sheet-like printing original plate P by an ink jet recording method. In the main scanning direction, the support base 12 for supporting the printing original plate P, the inkjet head 14 for discharging the photocurable ink imagewise onto the printing original plate P, and the photocurable ink discharged on the printing original plate P in the main scanning direction. A scanning UV (ultraviolet or ultraviolet) irradiation unit 16 that scans and irradiates in the direction indicated by the arrow Y in FIG. 1, a head moving mechanism 18 that moves the inkjet head 14 in the Y direction, which is the main scanning direction, A transport mechanism 20 that transports the printing original plate P supported by the support base 12 in a sub-scanning direction (direction indicated by an arrow X in FIGS. 1 and 2) substantially orthogonal to the main scanning direction (Y direction); Ttoheddo 14, the scanning UV irradiation section 16, and a control unit 22 for controlling the operation of the head moving mechanism 18 and the transport mechanism 20.

  The support base 12 has a flat plate shape and supports the printing original plate P supplied from an automatic plate feeding apparatus (not shown) on the surface thereof. Here, it is preferable to provide an air suction hole on the surface of the support base 12 to adsorb the printing original plate P during drawing by the inkjet head 14. Thereby, the flatness of the printing original plate P can be maintained appropriately. Further, when the printing original plate P is conveyed in the sub-scanning direction (X direction) by the conveying mechanism 20, it is preferable that the surface of the support base 12 has a small friction with the back surface of the printing original plate P. The support base 12 is attached to a plate making apparatus housing (not shown).

The transport mechanism 20 transports the printing original plate P to the inkjet head 14 in the sub-scanning (X) direction, and is a feed roller 30 that is a drive roller connected to a drive source (not shown) and a driven roller. The printing original plate P is sandwiched between the feed roller 30 and the suppression roller 32 and conveyed in the sub-scanning (X) direction. The feed roller 30 and the suppression roller 32 are arranged with the transport path of the printing original plate P sandwiched vertically. The printing original plate P supplied from the automatic plate feeder is sandwiched between the feed roller 30 and the suppression roller 32 with a predetermined nip pressure, and the feed roller 30 is rotated in a predetermined direction (counterclockwise in FIG. 2) by a driving source (not shown). ) Is conveyed in the sub-scanning (X) direction.
Here, when the printing original plate P is attracted to the surface of the support 12 during drawing by the inkjet head 14, the feed roller 30 and the suppression roller 32 stop rotating, and during non-drawing by the inkjet head 14, It is preferable that the feed roller 30 is rotationally driven by a drive source (not shown) and the printing original plate P sandwiched between the feed roller 30 is conveyed in the sub-scanning (X) direction. That is, it is preferable that the transport mechanism 20 intermittently sub-scans and transports the printing original plate P. Both the feed roller 30 and the restraining roller 32 are rotatably supported by a plate making apparatus casing (not shown).
The transport mechanism 20 used in the present invention may be anything as long as it can transport the printing original plate P in the sub-scanning direction, and all known sub-scan transport mechanisms can be applied.

The inkjet head 14 is disposed above the recording surface of the printing original plate P in the drawing so as to face the support table 12, and is in a main scanning (Y) direction parallel to the surface of the support table 12 by a head moving mechanism 18 described later. Are supported in a state where they can be reciprocated (scanned).
The inkjet head 14 ejects UV ink as ink droplets in an image-like manner onto the recording surface of the printing original plate P placed on the support base 12, that is, an ejection signal based on image data of an image to be recorded. Accordingly, UV ink is ejected and an image is recorded on the printing original plate P to form an ink-philic image portion. Here, the ejection signal is an ejection signal for ejecting droplets so as to selectively apply ink to a portion to be an image portion based on an image data signal of an image to be recorded. The recording surface of the printing original plate P exhibits ink repellency (hydrophilicity), and only the image portion formed by discharging the UV ink exhibits ink affinity (hydrophobicity).

  Here, as the inkjet head 14, various types of inkjet heads (ejection heads) such as a continuous type and an on-demand type piezo system, a thermal system, a solid system, and an electrostatic suction system can be used. It is preferable to use various types of on-demand ink jet heads. An example of an inkjet head that can be suitably used in the present invention will be described in detail later.

The head moving mechanism 18 reciprocates (scans) the inkjet head 14 in the main scanning direction, and includes a drive screw 34, a guide rail 35, a drive support portion 36a, and a support portion 36b.
Both the drive screw 34 and the guide rail 35 are parallel to the main scanning direction (Y direction in FIG. 1) orthogonal to the transport direction (X direction in FIG. 1) of the printing original plate P, and are the largest usable printing original plate. It arrange | positions so that P may be straddled from the left end to the right end.
The drive screw 34 is composed of a ball screw (not shown) having a male screw portion (not shown) that is screwed with a female screw portion (not shown) formed on the ink jet head 14, and moves the ink jet head 14 by rotating. The guide rail 35 is a guide that is inserted through a through-hole formed in the inkjet head 14 and guides the posture of the inkjet head 14 that is moved by the rotation of the drive screw 34 so as not to change.
The drive support portion 36a is provided at one end portion of the drive screw 34 and the guide rail 35, and the support portion 36b is provided at the other end portion thereof, and supports the drive screw 34 in a state where the drive screw 34 can be rotated forward and backward. The guide rail 35 is supported so as not to move. The drive support portion 36 a includes a drive source (not shown) such as a motor that drives the drive screw 34. The drive support portion 36a and the support portion 36b are both supported by the plate making apparatus casing (not shown) described above.

The inkjet head 14 is movably supported by a drive screw 34 and a guide rail 35. The drive screw 34 is rotated forward and backward by a drive support portion 36a, so that the ink jet head 14 is guided by the guide rail 35 while being guided in the Y direction (main scanning). Direction). The head moving mechanism 18 may include a plurality of guide rails or other posture holding means in order to maintain the posture of the inkjet head 14. The ink jet head 14 is moved by the guide rail 35 while maintaining a predetermined posture in which a portion for ejecting ink droplets faces the support base 12.
Here, the moving mechanism of the inkjet head 14 is not limited to the head moving mechanism 18 described above, and various known moving mechanisms can be used. For example, the drive screw is a rod-like member such as a guide rail, and guide wires are attached to both sides of the Y direction end of the inkjet head, and the guide wire in the moving direction is wound and moved along the guide rail. Can also be used. Further, a rack and pinion mechanism may be used. Moreover, it is good also as a self-propelled type. Further, a linear motor may be used.

The scanning UV irradiation unit 16 is disposed on the downstream side (backward in the sub-scanning (X) direction) of the printing original P so as to face the support table 12 and be separated from the inkjet head 14 by a predetermined distance L. The recording surface of the printing original plate P is irradiated with UV light while scanning in the main scanning (Y) direction, and is ejected imagewise onto the recording surface of the printing original plate P to cure the UV ink forming the image portion. Is. In the present invention, the distance between the inkjet head 14 and the scanning UV irradiation unit 16 refers to the position of the ejection nozzle of the inkjet head 14, and in the case of a nozzle array, the center position in the sub-scanning direction (X) and the scanning type. This is the distance between the position of the UV lamp 40 of the UV irradiation unit 16 and the center position of the UV lamp 40 in the sub-scanning direction (X).
As shown in FIGS. 3 (a) and 3 (b), the scanning UV irradiating unit 16 is placed outside the transport path of the printing original P, and emits UV light, and is emitted from the UV lamp 40. The reflected UV light is parallel light parallel to the recording surface of the printing original plate P supported on the support table 12, and the parallel UV light generated by the reflector 42 is reflected to the printing original plate P side. The scanning mirror 44 is movable in the scanning direction, and the mirror moving mechanism 46 is configured to reciprocate (scan) the scanning mirror 44 in the main scanning (Y) direction.

  The mirror moving mechanism 46 is arranged in parallel with the sub-scanning (X) direction on both outer sides of the support base 12 or the maximum usable printing original P transport path, that is, both outer sides in the main scanning (Y) direction. It has two conveying rollers 48a and 48b, an endless belt 50 stretched around these two conveying rollers 48a and 48b, and a drive source (motor) 52 that rotationally drives the conveying rollers 48a. The scanning mirror 44 is formed on the inner surface (belt portion 50b side) of the belt portion 50a on the one printing original plate P (support base 12) side of the belt portions 50a and 50b facing the endless belt 50 between the conveying rollers 48a and 48b. Is attached at a predetermined angle, which is inclined by approximately 45 ° in FIG. An irradiation window 54 that transmits the irradiation light reflected by the scanning mirror 44 is formed in the belt portion 50a of the endless belt 50 adjacent to the mounting position of the scanning mirror 44. Further, on both sides of the endless belt 50 of the mirror moving mechanism 46 of the scanning UV irradiation unit 16 in the sub-scanning (X) direction, two mirror plates 56a and 56b whose inner portions facing each other form a mirror surface are arranged. . In addition, as for belt part 50a and 50b of the endless belt 50, it is preferable that the inner part which mutually opposes makes a mirror surface.

  In the scanning UV irradiation unit 16, the transport roller 48 a is driven to rotate by the drive motor 52 of the mirror moving mechanism 46, and the endless belt 50 stretched between the transport rollers 48 a and 48 b is rotated, for example, in the drawing. The scanning mirror 44 attached to the belt portion 50a of the endless belt 50 that rotates to the right is moved (scanned) from the upper right end of the printing original plate P on the support base 12 to the upper left end in the arrow X direction (main scanning direction). Then, the UV light having a rectangular cross section reflected by the scanning mirror 44 is scanned from the right end to the left end in the drawing while irradiating the printing original plate P. Thereafter, the transport roller 48a is rotated in the reverse direction, the endless belt 50 is rotated in the reverse direction in the figure, and the scanning mirror 44 attached to the endless belt 50 rotating in the left direction in the figure is attached to the printing original plate on the support base 12. P is moved (scanned) in the direction of the arrow X from the upper left end to the upper right end in the drawing of P, and the scanning mirror 44 is scanned from the left end to the right end in the drawing while irradiating UV light having a rectangular cross section on the printing original P.

  The UV lamp 40 is for irradiating UV light onto the image portion formed of the UV ink on the printing original plate P by the ink jet head 14 to cure the UV ink. As the UV lamp 40, for example, various lamps (point light sources) such as ultra-high pressure mercury lamps and metal halide lamps, tube bulbs such as ultraviolet fluorescent tubes, and lamps made substantially dotted using these can be used. . These light sources may emit light including visible light. When the photosensitive area of the photocurable ink (in this embodiment, UV ink) has sensitivity in the visible light range, the sensitivity can be further increased by irradiating light including visible light. The ink can be suitably cured. In the present invention, if the apparatus cost is not taken into consideration, it is possible to use a UVLED or a UVLED array instead of the UV lamp 40, but this is not preferable because of high cost.

The reflector 42 has a built-in UV lamp 40 and includes a rectangular cross-section injection port 42a that emits UV light emitted from the UV lamp 40 as parallel light having a rectangular cross-section. The inner surface of the reflector 42 is a mirror surface, and the UV light emitted from the UV lamp 40 is reflected without being absorbed by the inner surface, and all is emitted as rectangular parallel UV light from the emission port 42a.
The reflector 42 incorporating the UV lamp 40 is disposed between the belt portions 50a and 50b facing the endless belt 50 and in the vicinity of the conveyance roller 48a with its injection port 42a facing the conveyance roller 48b. Thus, the parallel UV light having a rectangular cross-section emitted from the emission port 42a of the reflector 42 is opposed between the conveying rollers 48a and 48b, between the belt portions 50a and 50b whose inner surfaces facing each other of the endless belt 50 are mirror surfaces, and each other. It travels through a waveguide 58 having a rectangular cross section formed by a substantially rectangular parallelepiped space formed between two mirror plates 56a and 56b whose inner surfaces are mirror surfaces.

The scanning mirror 44 is fixed at a predetermined position on the inner surface of the belt portion 50a of the endless belt 50 by being inclined by approximately 45 °. The scanning mirror 44 needs to be fixed to the inner surface of the belt portion 50a so that the inclination angle does not change in the reciprocal movement. However, if this can be realized, the fixing method of the scanning mirror 44 to the inner surface of the belt portion 50a is particularly limited. It is not something.
The scanning mirror 44 emits parallel UV light having a rectangular cross section, which is emitted from the UV lamp 40 and emitted from the emission port 42a of the reflector 42, and travels through a waveguide 58 having four inner peripheral surfaces formed as mirror surfaces. Reflected toward the illumination window 54 formed in the belt portion 50a. The UV light having a rectangular cross section reflected by the scanning mirror 44 passes through the illumination window 54 and is irradiated onto the printing original plate P placed on the support table 12. At this time, the scanning mirror 44 is similarly reciprocated together with the endless belt 50 reciprocated in the arrow Y direction (main scanning direction) by the mirror moving mechanism 46, so that the cross section of the rectangular shape reflected by the scanning mirror 44 is formed. The UV light scans back and forth while irradiating the recording surface of the printing original plate P.
The scanning mirror 44 may be any reflection mirror as long as it can reflect parallel UV light having a rectangular cross section, but is preferably a total reflection mirror that can reflect all light. The illumination window 54 may be a rectangular opening formed in the belt portion 50a of the endless belt 50, or may be formed in the belt portion 50a of the endless belt 50 by a rectangular transparent resin film or a transparent member. May be.

Here, the endless belt 50 of the mirror moving mechanism 46 may be of any type as long as it has a predetermined strength even if the inner surface is a mirror surface and the illumination window 54 is formed in a part thereof. For example, an endless belt made of stainless steel (stainless steel belt) is preferable.
The conveying rollers 48 a and 48 b that stretch the endless belt 50 have a diameter larger than the height of the reflector 42 in which the UV lamp 40 is built, and are longer than the belt width of the endless belt 50 that is longer than the longitudinal length of the reflector 42. It should be a little longer. The transport rollers 48a and 48b are both rotatably supported by the above-described plate making apparatus housing (not shown) via a bearing or the like, for example.
The drive source 52 may be anything as long as it can rotate the transport roller 48a in the forward direction and the reverse direction. For example, an electric motor can be used, and the drive source 52 can be directly connected to the rotation shaft of the transport roller 48a. Alternatively, it may be connected via a transmission device such as a belt transmission using a belt and a pulley or a gear transmission. The drive source 52 is also supported by the above-described plate making apparatus housing (not shown).

  Further, as described above, the mirror plates 56a and 56b are provided in parallel on both sides of the endless belt 50 of the mirror moving mechanism 46 so that the mirror surfaces thereof are opposed to each other. A rectangular cross-section guide through which parallel UV light having a rectangular cross section emitted from the UV lamp 40 and emitted from the outlet 42a of the reflector 42 travels by the mirror surfaces of the inner surfaces of the belt portions 50a and 50b facing the endless belt 50. This is for forming the waveguide 58. For this reason, the mirror plates 56a and 56b may be anything as long as at least the inner surface is a mirror surface, but covers the scanning range (reciprocating range) of the scanning mirror 44 fixed to the endless belt 50. It has a length, that is, a length that covers at least the range from the injection port 42a of the reflector 42 to the vicinity of the conveying roller 48b, and preferably has a length that covers a range slightly larger than this range. The inner surface having a width that covers the range of the belt portions 50a and 50b, preferably a slightly larger range, may be a flat plate having a mirror surface.

As described above, the control unit 22 controls the operations of the inkjet head 14, the scanning UV irradiation unit 16, the head moving mechanism 18, and the transport mechanism 20. Specifically, the control unit 22 discharges UV ink according to image data by the inkjet head 14 to form an image portion on the printing original plate P, and UV ink forming the image portion on the printing original plate P. Scanning light irradiation by the scanning UV irradiation unit 16, particularly a mirror moving mechanism of the scanning mirror 44 that is emitted from the UV lamp 40 and reflects the UV light emitted from the exit 42 a of the reflector 42. 46 controls reciprocation (main scanning) by 46, reciprocation (main scanning) of the inkjet head 14 in the main scanning direction by the head moving mechanism 18, and sub-scanning conveyance (preferably, intermittent conveyance) of the printing original plate P by the conveyance mechanism 20. .
In addition, it is preferable that the control part 22 controls the whole plate-making apparatus 10 or all the components which are not shown in figure.

The operation of the plate making apparatus shown in FIG. 1 to FIG. 3 will be described below, so that the operation of the ink jet drawing apparatus according to the first aspect of the present invention and the ink jet drawing method according to the second aspect of the present invention are applied. A method for preparing a lithographic printing plate will be described.
In the plate making apparatus 10 shown in FIGS. 1 to 3, the printing original plate P is supplied to the support table 12 from an automatic plate feeding apparatus (not shown).
The printing original plate P supplied to the support base 12 is conveyed by the conveyance mechanism 20 at a predetermined speed in the sub-scanning direction (X direction in FIG. 1).

The printing original plate P is transported to a position facing the inkjet head 14 by the transport mechanism 20. The inkjet head 14 ejects UV ink onto the surface of the printing original plate P according to the image signal while being moved in the main scanning direction by the head moving mechanism 18. As a result, an image portion is formed on the surface of the printing original plate P by the UV ink.
Here, the inkjet head 14 is moved by the conveyance mechanism 20 in the sub-scanning direction and the inkjet head 14 is moved back and forth in the main scanning direction (Y direction in FIG. 1) by the head moving mechanism 18. Are scanned to form an image portion with UV ink at a required position on the entire surface of the printing original P.

The printing original plate P that has passed the position facing the inkjet head 14 is then conveyed to a position facing the scanning UV irradiation unit 16. As described above, the scanning UV irradiation unit 16 causes the scanning mirror 44 that reflects parallel UV light having a rectangular cross-section emitted from the UV lamp 40 by the mirror moving mechanism 46 onto the recording surface of the printing original P to be in the main scanning direction. The UV light reflected by the scanning mirror 44 is irradiated onto the UV ink of the image portion formed on the recording surface of the printing original plate P while being reciprocated. That is, the scanning mirror 44 that reflects the UV light emitted from the UV lamp 40 is moved in the main scanning direction, and serial scanning of the scanning mirror 44 with respect to the printing original plate P is performed, similarly to the inkjet head 14 described above. The entire surface of the printing original plate can be irradiated with UV light reflected by the scanning mirror 44.
Here, the UV ink formed as an image portion on the surface (recording surface) of the printing original plate P is emitted from the UV lamp 40 and irradiated with UV light having a rectangular cross section reflected by the scanning mirror 44. Cured.
The printing original plate P whose image portion is cured by UV light emitted from the UV lamp 16 is further transported in the sub-scanning direction (X direction in FIG. 1) and transported to the next process, or as a completed printing plate It is discharged from the plate making apparatus 10.

  Here, in the present invention, the inkjet head 14 and the scanning UV irradiating unit 16 specifically include the center in the X direction of the inkjet head 14 (the center in the X direction of the array of ejection nozzles) and the scanning UV irradiation. The center of the part 16 in the X direction (the center of the UV lamp 40 in the X direction) is set to be separated by a distance L or more. The distance L is influenced by the heat of the UV lamp 40, specifically, heat radiated from the UV lamp 40 itself and heat rays (heat component) included in the UV light emitted from the UV lamp 40 and irradiated on the printing original plate P. ) Is the distance that does not affect the drawing by the inkjet head 14, the drawing speed by the inkjet head 14, the type or structure of the inkjet head 14 and the UV lamp 40, the sub-scanning conveyance speed of the printing original P The distance is determined based on various conditions such as the material or the material of the printing original plate P and the amount of UV light irradiated from the UV lamp 40 to the printing original plate P.

By setting the distance between the inkjet head 14 and the scanning UV irradiation unit 16 (UV lamp 40) to L or more, the printing original plate P is heated by UV light having a thermal component irradiated from the UV lamp 40 or emitted heat. It is possible to prevent distortion of the printing original plate P due to thermal expansion caused by being generated at an image recording position (UV ink droplet landing position) by the ink jet head 14, and accordingly, image recording on the printing original plate P by the ink jet head 14. Misalignment can be prevented.
By doing so, in the printing apparatus to which the present invention is applied, it is possible to produce a printing plate on which an image portion with high image recording position accuracy, high image quality, and high accuracy is formed. Even when multi-color printing is used, high-precision and high-quality printing without color misregistration can be performed.

Here, the distance L (cm) is the maximum temperature of the printing original plate at the time of UV light irradiation, that is, when the temperature difference between the temperature of the printing original plate P and the room temperature at the center point of the UV light irradiation region is dt (° C.). Furthermore, it is preferable to set it as 0.5 * dt or more, and it is more preferable to set it as 1.0 * dt or more.
By setting the distance L to 0.5 × dt or more, it is possible to form an image with higher image recording position accuracy, high image quality and high accuracy, and further to 1.0 × dt or more. The above effects can be obtained more suitably.
In order to obtain these effects, it is not necessary to set an upper limit value. However, if the distance L is increased, there is a problem that the ink spreading width on the printing original plate P is enlarged, and the apparatus is enlarged. Therefore, it is preferable that the distance L is 2.5 × dt or less. By doing so, it is possible to prevent the ink from spreading on the printing original plate P from being enlarged, and to reduce the size of the apparatus.

Regardless of the recording speed by the inkjet head 14 with respect to the printing original plate P, the moving (scanning) speed of the scanning mirror 44 is adjusted by the mirror moving mechanism 46, and accordingly, the scanning speed of the scanning UV light reflected by the scanning mirror 44 is adjusted. Thus, the irradiation time at each position of the printing original plate P can be adjusted.
Thereby, the irradiation amount (irradiation energy) of the UV light applied to the UV ink of the image portion formed by the inkjet head 14 can be adjusted. For example, the UV ink of the image portion can be kept constant. Curing can be performed properly.
Further, the irradiation amount of irradiation UV light (irradiation energy = light amount per unit time × irradiation time) at each position of the printing original plate P is adjusted without adjusting the light amount of the UV light emitted from the UV lamp 40. be able to.
Further, even when the amount of light changes with time as the UV lamp 40 is used, the printing original plate is adjusted by adjusting the moving speed of the scanning mirror 44, that is, the scanning speed of the scanning UV light, according to the amount of light emitted from the UV lamp 40. It is possible to irradiate P with a certain amount of UV light.

Note that the rate of change in the scanning speed of the UV light may be adjusted according to the material of the printing original P, the material of the UV ink, the image forming method, and the like.
In addition, even when the light amount of the UV lamp 40 changes with time, the ink can be cured with a constant irradiation light amount by changing the scanning speed of the UV light. Specifically, when the irradiation light amount of the UV lamp 40 is reduced to ½ over time, the scanning speed of the UV light is halved so that the irradiation amount on the printing original plate is the same as that at the start of use. The UV ink can be cured.

As mentioned above, although each component of the plate-making apparatus 10 of one Embodiment of this invention was demonstrated in detail, this invention is not limited to this.
For example, in the above-described embodiment, since the apparatus cost can be reduced, the serial head that moves the inkjet head in the main scanning direction is used. An inkjet head having a shape longer than the width, that is, an inkjet head may be used as a line head.
The plate making apparatus to which the present invention is applied is basically configured as described above.

In the plate making apparatus 10 according to the above-described embodiment, the inkjet head 14 and the scanning UV irradiation unit 16 are arranged apart from each other by a predetermined distance equal to or more than the distance L. However, like the plate making apparatus 60 shown in FIG. In addition, the scanning UV irradiation unit 16 may be movable in the sub-scanning direction with respect to the inkjet head 14 and the distance L may be adjusted. In the present invention, as in the plate making apparatus 60 shown in FIG. 4, the UV ink ejected imagewise onto the printing original plate P by the inkjet head 14 is cured by scanning UV light from the scanning UV irradiation unit 16. In order to protect the image portion thus formed, a plate surface protective liquid (hereinafter referred to as gum liquid) may be applied.
FIG. 4 is a schematic top view showing a schematic configuration of another embodiment of the plate making apparatus to which the ink jet drawing apparatus according to the present invention is applied. FIG. 5 is a schematic front view of a scanning UV (ultraviolet) irradiation unit and an irradiation unit moving mechanism of the plate making apparatus shown in FIG.

The plate making apparatus 60 shown in FIG. 4 is the same as the plate making apparatus shown in FIGS. 1 to 3 except for the supporting portion of the scanning UV irradiation unit 16, the irradiation unit moving mechanism 24, the gum solution discharge head 26, and the head moving mechanism 28. 10, the same components are denoted by the same reference numerals, and detailed description thereof is omitted. Mainly, the irradiation unit moving mechanism 24, the gum solution discharge head 26, and the head The moving mechanism 28 will be described.
A plate making apparatus 60 shown in FIG. 4 includes a support 12, an inkjet head 14, a scanning UV irradiation unit 16, a head moving mechanism 18, a transport mechanism 20, a control unit 22, and a scanning UV irradiation unit 16. An irradiation unit moving mechanism 24 that reciprocates in the sub-scanning direction (X direction) with respect to the inkjet head 14, and image-like drawing with UV ink by the inkjet head 14, and curing by scanning UV light by the scanning UV irradiation unit 16. A gum solution ejection head 26 that ejects the gum solution onto the printing original plate P on which the image portion is formed, and a head moving mechanism 28 that moves the gum solution ejection head in the main scanning direction (Y direction).
In the plate making apparatus 60 shown in FIG. 4, the control unit 22 includes the irradiation unit moving mechanism 24, the gum solution discharge head in addition to the operations of the inkjet head 14, the scanning UV irradiation unit 16, the head moving mechanism 18, and the transport mechanism 20. The operation of the head 26 and the head moving mechanism 28 is also controlled.

As shown in FIGS. 4 and 5, the scanning UV irradiation unit 16 further includes support legs 62a, 62b and 63a, 63b that rotatably support the rotation shafts of the transport rollers 48a and 48b from both sides, respectively. A support member 64 a that supports the support legs 62 a and 62 b and the driving source 52 and a support member 64 b that supports the support legs 63 a and 63 b are provided, and these constitute a support portion of the scanning UV irradiation unit 16.
The irradiation unit moving mechanism 24 reciprocates (scans) the scanning UV irradiation unit 16 in the sub-scanning direction (X direction), that is, moves on a plane spaced apart from the surface of the support 12 by a predetermined distance. Screws 66a and 66b, guide rails 67a and 67b, drive support portions 68a and 70a, and support portions 68b and 70b are provided.

Next, the drive screws 66a and 66b and the guide rails 67a and 67b are arranged in parallel with the sub-scanning direction.
Further, the drive screws 66a and 66b are each composed of a ball screw (not shown) having a male screw part (not shown) that is screwed with a female screw part (not shown) formed on the support members 64a and 64b, and the like. The support members 64a and 64b are moved. The guide rails 67a and 67b are inserted through through holes formed in the support members 64a and 64b, respectively, and guide the support members 64a and 64b that move by the rotation of the drive screws 66a and 66b so that the postures thereof do not change. It is a guide.

The drive support portion 68a is provided at one end portion of the drive screw 66a and the guide rail 67a, and the support portion 68b is provided at the other end portion thereof, and supports the drive screw 66a in a state in which the drive screw 66a can rotate forward and backward. A guide rail 67a is also supported. The drive support portion 70a is provided at one end portion of the drive screw 66b and the guide rail 67b, and the support portion 70b is provided at the other end portion thereof, and supports the drive screw 66b in a state in which forward and reverse rotation is possible. In addition, a guide rail 67b is also supported.
Here, the drive support portions 68a and 70a include drive sources (not shown) such as motors for driving the drive screws 66a and 66b, respectively. The drive support portions 68a and 70a and the support portions 68b and 70b are both supported by the above-described plate making apparatus casing (not shown).

Here, the drive support portions 68a, the support portions 68b and the drive support portions 70a, and the support portions 70b rotate the drive screws 66a and 66b, so that the support members 64a and 64b are being guided by the guide rails 67a and 67b. Are moved in the sub-scanning direction (X direction). When the support members 64a and 64b are moved in the sub-scanning direction, the scanning UV irradiation unit 16 supported by the support legs 62a, 62b and 63a, 63b on the support members 64a and 64b, respectively, also in the sub-scanning direction. Moved. Thus, the scanning UV irradiation unit 16 can be moved in the sub-scanning direction, and the UV lamp 40, the endless belt 50, and the scanning mirror 44 can also be moved in the sub-scanning direction. The scanning UV light reflected by the scanning mirror 44 can also move in the sub-scanning direction.
At this time, the drive support portions 68a and 70a are positioned so that the positions of the support members 64a and 64b in the sub-scanning direction are the same, that is, the scanning UV irradiation unit 16 is not inclined in the sub-scanning direction. The support members 64a and 64b are moved synchronously.

The irradiation unit moving mechanism 24 may include a plurality of guide rails or other posture holding means in order to maintain the posture of the scanning UV irradiation unit 16. The scanning UV irradiation unit 16 is moved by the drive screws 66a and 66b and the guide rails 67a and 67b while maintaining a predetermined posture facing the support base 12.
Here, the moving mechanism of the scanning UV irradiation unit 16 is not limited to the irradiation unit moving mechanism 24 described above, and various known moving mechanisms can be used. For example, either one of the drive screws 66a and 66b may be used as a guide rail, and the drive support portion may be used as a support portion, and the support members 64a and 64b may be moved by only one drive screw, or the support member 64a. And 64b are connected to form an integrated support member, and an opening is provided in the scanning region of the UV light by the scanning mirror 44 of the scanning UV irradiation unit 16 so as to move on the printing original plate P in the sub-scanning direction. good.

The drive screw is a rod-shaped member such as a guide rail, and guide wires are provided on both sides of each end in the Y direction of each of the support members 64a and 64b. It is also possible to use a configuration in which the robot is moved. Further, a rack and pinion mechanism may be used. Moreover, it is good also as a self-propelled type. Further, a linear motor may be used.
Further, the transport rollers 48a and 48b of the scanning UV irradiation unit 16 are formed as outer cylinders as cylindrical members, and a female screw that is screwed with a male screw of a drive screw is provided at the center of the inner cylinder that rotatably supports the outer cylinder, By rotating the drive screw, the outer cylinder and the inner cylinder are moved synchronously in the sub-scanning direction, while the outer cylinder is rotated with respect to the inner cylinder by the drive source 52, thereby rotating the transport rollers 48a and 48b. The endless belt 50 may be rotated.

Here, in the present embodiment, the control unit 22 controls the head moving mechanism 18 and the irradiation unit moving mechanism 24 so that the inkjet head 14 and the scanning UV irradiation unit 16 (UV lamp 40) are separated by a distance L or more. Although it is preferable, the adjustment of the distance L by the irradiation unit moving mechanism 24 may be performed manually.
Thus, in the present embodiment, the UV light emitted from the UV lamp 40 can be moved in both the main scanning direction and the sub-scanning direction. As described above, the UV light emitted from the UV lamp 40 is added to the main scanning direction by the scanning UV irradiation unit 16 and the irradiation unit moving mechanism 24 and is also moved in the sub scanning direction. The relative speed between P and the scanning UV irradiation unit 16 (UV light emitted from the UV lamp 40), the drawing speed by the ink jet head 14 described above, the type or structure of the ink jet head 14 and the UV lamp 40, the sub-printing plate P The distance L can be adjusted according to the scanning conveyance speed, the material or the material of the printing original plate P, the amount of UV light irradiated from the UV lamp 40 to the printing original plate P, and the like. Thereby, the distance L between the inkjet head and the scanning UV irradiation unit 16 (scanning UV light) can be adjusted to a suitable range by the control unit 22 under various conditions.

Further, by enabling the scanning UV irradiation unit 16 and thus the UV lamp 40 to move in the sub-scanning direction, the transport mechanism 20 transports the printing original plate P and moves the UV lamp 40 and thus the scanning UV light in the main and sub-scanning directions. And the relative speed can be adjusted. That is, the relative speed between the inkjet head 14 and the printing original plate P in the sub-scanning direction and the relative speed between the scanning UV light (UV lamp 40) and the printing original plate P in the sub-scanning direction can be different.
As a result, even when the drawing (recording) speed by the inkjet head 14 and the optimum moving speed of the scanning UV light (UV lamp 40) are different, printing is performed by moving in the sub-scanning direction while moving in the main scanning direction. The irradiation time at each position of the original plate can also be adjusted. That is, the drawing speed of the inkjet head 14 with respect to the printing original plate P and the moving speed of the scanning UV light with respect to the printing original plate P can be set to different speeds. Thereby, the drawing (image recording) by the inkjet head 14 and the curing of the UV ink by the scanning UV light can be suitably performed. In addition, the amount of scanning UV light at each position of the printing original P can be adjusted without adjusting the amount of UV light emitted from the UV lamp 40. Furthermore, even when the light amount of the UV lamp 40 changes with use, the printing original plate P can be irradiated with a constant light amount by adjusting the moving speed according to the light amount of the UV lamp 40.

Here, the moving speed of the scanning UV light emitted from the UV lamp 40 is preferably changed in multiple steps or continuously in both the main scanning direction and the sub-scanning direction.
By changing the moving speed of the scanning UV light in multiple steps or continuously, the light quantity at each position of the printing original plate P can be adjusted. Adjustment of the moving speed of scanning UV light according to the area ratio or image density of the image portion, that is, the scanning speed of UV light, the adjustment rate (speed change rate), and the proper curing of the UV ink of the printing original plate P by these adjustments The increase in efficiency and efficiency may be performed in the same manner as in the case of the movement (scanning) speed of the scanning UV light in the main scanning direction.

The gum solution discharge head 26 is printed on a printing original plate P having an image portion that is imagewise drawn with UV ink by the inkjet head 14 and that is formed by curing the UV ink by scanning UV light by the scanning UV irradiation unit 16. A plate surface protecting liquid (hereinafter simply referred to as a gum solution) for protecting the surface of the plate on which the image portion of the plate is formed, is discharged in the sub-scanning conveyance direction of the printing original plate P. It is arranged on the downstream side so as to face the support base 12.
The gum solution discharge head 26 preferably discharges the gum solution onto the plate surface of the printing original plate P in which the image portion is formed by the inkjet head 14 and the UV ink is cured by the UV lamp 40, and is preferably applied to the plate surface of the printing original plate P. Discharges the gum solution in accordance with a predetermined gum solution ejection signal, and forms a gum solution film on the non-image portion of the printing original plate P.

Here, the gum solution discharge signal is, for example, a discharge signal for discharging droplets so as to selectively apply the gum solution to a portion to be a non-image portion based on an image signal. Note that when a gum solution is applied to a non-image portion as in this embodiment, an ink ejection signal (hereinafter also simply referred to as an ejection signal) for controlling ejection of ink droplets of the inkjet head 14 is used as the gum solution ejection signal. ) Can be used.
As the gum solution discharge head 26, various types of inkjet heads can be used in the same manner as the inkjet head 14. As the gum solution discharge head 26, it is particularly preferable to use an ink-jet head using an on-demand piezo method or a thermal method. Here, an ink jet head having a lower resolution than the ink jet head 14 can also be used as the gum solution discharge head 26.

The head moving mechanism 28 is for moving the gum solution discharge head 26 in the main scanning direction (Y direction), and has a drive screw 72, a guide rail 73, a drive support portion 74a, and a support portion 74b. Basically, the head moving mechanism 18 has the same configuration.
Both the drive screw 72 and the guide rail 73 are parallel to the main scanning direction (Y direction in FIG. 1) orthogonal to the transport direction (X direction in FIG. 1) of the printing original plate P, and are the largest usable printing original plate. It arrange | positions so that P may be straddled from the left end to the right end.
The drive screw 72 includes a ball screw (not shown) having a male screw portion (not shown) that is screwed with a female screw portion (not shown) formed in the gum solution discharge head 26, and rotates the gum solution discharge head 26 by rotating. Move in the main scanning direction. The guide rail 73 is a guide that is inserted through a through-hole formed in the gum solution discharge head 26 and guides the posture of the gum solution discharge head 26 that moves as the drive screw 72 rotates.
The drive support portion 74a is provided at one end portion of the drive screw 72 and the guide rail 73, and the support portion 74b is provided at the other end portion thereof, and supports the drive screw 72 in a state where the drive screw 72 can be rotated forward and backward. The guide rail 73 is supported so as not to move. The drive support portion 74 a includes a drive source (not shown) such as a motor that drives the drive screw 72. The drive support portion 74a and the support portion 74b are both supported by the plate making apparatus casing (not shown) described above.

The gum solution discharge head 26 is supported by a drive screw 72 and a guide rail 73 so as to be movable, and the drive screw 72 is rotated forward and backward by a drive support portion 74a, thereby being guided by the guide rail 73 and in the Y direction ( It is reciprocated (scanned) in the main scanning direction. The head moving mechanism 28 may include a plurality of guide rails or other posture holding means in order to maintain the posture of the gum solution discharge head 26. The gum solution discharge head 26 is moved by the guide rail 73 while maintaining a predetermined posture in which a portion for discharging the gum solution is opposed to the support 12.
Here, the moving mechanism of the gum solution discharge head 26 is not limited to the head moving mechanism 28 described above, and various known moving mechanisms can be used in the same manner as the head moving mechanism 18. For example, the drive screw is a rod-shaped member such as a guide rail, and guide wires are attached to both sides of the Y-direction end of the gum solution discharge head. The guide wire in the moving direction is wound up and moved along the guide rail. The structure to make can also be used. Further, a rack and pinion mechanism may be used. Moreover, it is good also as a self-propelled type. Further, a linear motor may be used.

  The gum solution discharge head 26 is moved in the main scanning direction by the head moving mechanism 28 and, as a preferred mode, discharges the gum solution according to the gum solution discharge signal and forms a gum solution film on the printing original plate P. As described above, the gum solution is ejected using the gum solution ejection head 26 in accordance with the gum solution ejection signal, so that it is selective to a necessary portion, particularly a non-image portion, according to the position of the image portion of the printing original plate P. A gum liquid film can be formed. Thereby, a gum solution can be used efficiently. Thus, by discharging the gum solution only to the non-image area and forming only the non-image area, the gum solution can be used more efficiently without waste, and the consumption of the gum solution is reduced. can do.

In the above embodiment, the gum liquid is ejected while moving the gum liquid ejection head in the main scanning direction (Y direction in the figure). However, the present invention is not limited to this, and the main scanning of the printing original plate You may provide in the whole direction. That is, the gum solution discharge head may be a line head that is longer than the length of the printing original plate in the main scanning direction.
In addition, it is preferable to use a gum solution discharge head as in this embodiment in that the gum solution can be used efficiently as described above, but the present invention is not limited to this, and a roll coater method or a spray method The gum solution may be applied to the entire surface of the printing original plate by the gum solution application mechanism.
Further, in the sub-scanning direction of the printing original plate, a heating device for drying the gum liquid film applied to the printing original plate may be provided on the downstream side of the gum liquid discharge head. Moreover, you may dry a gum liquid film by the residual heat by UV light irradiation.

In each of the above embodiments, the printing original plate P is transported in the sub-scanning direction by the transport mechanism 20, but the present invention is not limited to this, and scanning UV irradiation including an inkjet head and a UV lamp. The unit may be integrated and moved in the sub-scanning direction by a common moving mechanism.
FIG. 6A is a schematic top view showing a schematic configuration of another embodiment of a plate making apparatus to which the ink jet drawing apparatus of the present invention is applied, and FIG. 6B is a plate making shown in FIG. It is typical sectional drawing which shows schematic structure of an apparatus.
A plate making apparatus 80 shown in FIG. 6 is provided with the exception of the scanning table 82 on which the inkjet head 14 and the scanning UV irradiation unit 16 are placed and the transport mechanism 84 instead of the transport mechanism 20 that transports the printing original plate P in the sub-scanning manner. Since it has the same configuration as that of the plate making apparatus 10 shown in FIGS. 1 to 3, the same components are denoted by the same reference numerals, detailed description thereof is omitted, and the scanning table 82 and the conveyance are mainly used. The mechanism 84 will be described.

The plate making apparatus 80 shown in these drawings includes a support 12, an inkjet head 14, a scanning UV irradiation unit 16, a head moving mechanism 18, a control unit 22, an inkjet head 14 and a scanning UV irradiation unit 16. It has a scanning table 82 that is mounted as a unit, and a transport mechanism 84 that moves the scanning table 82 in the sub-scanning direction (X direction in the figure).
In the plate making apparatus 80 shown in FIG. 6, the control unit 22 controls operations of the inkjet head 14, the scanning UV irradiation unit 16, the head moving mechanism 18, and the transport mechanism 84.

The scanning table 82 is disposed to face the support table 12 and is moved in the sub-scanning direction by the transport mechanism 84. A scanning UV irradiation unit 16 including the inkjet head 14, the head moving mechanism 18, and the UV lamp 40 is placed on the scanning table 82. Also in this case, the distance between the inkjet head 14 and the scanning UV irradiation unit 16 (UV lamp 40) is adjusted so as to be separated by a distance L or more.
The drive support portion 36 a and the support portion 36 b of the head moving mechanism 18 are mounted on the scanning table 82. Further, the rotation shafts of the transport rollers 48a and 48b of the scanning UV irradiation unit 16 are rotatably supported by support legs 62a and 62b and 63a and 63b provided on the scanning table 82 from both sides thereof. The support legs 62a, 62b and 63a, 63b can be the same as those used in the plate making apparatus 60 shown in FIG.

The ink jet head 14, the head moving mechanism 18, and the scanning UV irradiation unit 16 are placed on the scanning table 82, and a predetermined sub-scanning is performed in the sub-scanning direction by the transport mechanism 84 on the printing original plate P fixed to the support table 12. Except for being transported together with the scanning table 82 at a speed, it operates in the same manner as the inkjet head 14, the head moving mechanism 18 and the scanning UV irradiation unit 16 of the plate making apparatus 10 shown in FIG. That is, the inkjet head 14 is moved in the main scanning direction by the head moving mechanism 18 on the scanning stage 82 that is being transported in the sub-scanning direction, and the UV light emitted from the UV lamp 40 of the scanning UV irradiation unit 16 is marked and reduced. The scanning mirror 44 that reflects toward the plate P is moved in the main scanning direction by the mirror moving mechanism 46.
For this reason, the scanning stage 82 has an opening 82a in the movement (scanning) area of the inkjet head 14 in the main scanning direction, and the movement (scanning) area of the scanning mirror 44 of the scanning UV irradiation unit 16 in the main scanning direction. That is, the opening 82b is formed in the main scanning region of the UV light.

The transport mechanism 84 is laid on a plate making apparatus (not shown) on bases 86a and 86b disposed on both outer sides of the support base 12 in parallel in the sub-scanning direction, and on the bases 86a and 86b in parallel in the sub-scanning direction. Guide rails 88a and 88b, a drive screw 90 disposed in the vicinity of the guide rails 88a and 88b, and support legs 92a and 92b provided on the back side of the scanning table 82 facing the guide rails 88a and 88b. Wheels 94 a and 94 b that can be supported, and a traveling nut 96 that is formed with a female screw to be engaged with a male screw formed on the drive screw 90 and is fixed to the back side of the scanning table 82.
The guide rails 88a and 88b and the drive screw 90 are preferably longer than the maximum length in the sub-scanning direction of the printing original plate P to be used. Both ends of the drive screw 90 are rotatably supported by two support legs (not shown), and are driven to rotate by a drive source (motor) (not shown). These support legs are fixed to a base 86a or a plate making apparatus main body (not shown). Further, it is preferable that two or more sets of support legs 92a and wheels 94a and sets of support legs 92b and wheels 94b are provided on the back side of the scanning table 82 along the sub-scanning direction.

In the transport mechanism 84, the wheels 94a of the support legs 92a and the wheels 94b of the support legs 92b of the scanning base 82 on which the inkjet head 14, the head moving mechanism 18, and the scanning UV irradiation unit 16 are placed are respectively connected to the base 86a and After being placed on the guide rails 88a and 88b on 86b, the drive screw 90 is rotated, and the traveling nut 96 is moved in the sub-scan transport direction, so that the scanning stage 82 is maintained in the proper posture and the sub-scan transport is performed. It can be moved (conveyed) in the direction.
Thus, in the plate making apparatus 80, the scanning stage 82 on which the inkjet head 14 and the scanning UV irradiation unit 16 are placed is placed in the sub-scanning direction (X direction) with respect to the printing original plate P fixed on the support stage 12. While moving, by moving the inkjet head 14 and the scanning mirror 44 (UV light) of the scanning UV irradiation unit 16 in the main scanning direction (Y direction), an image portion is formed in the entire area of the printing original P, and UV ink can be cured by irradiating the image portion formed on the printing original plate P with UV light.
Thus, a printing plate can be produced by performing drawing and ink curing while moving the inkjet head and the scanning UV irradiation unit 16 together in the sub-scanning direction.

  As described above, the control unit 22 controls the operations of the inkjet head 14, the scanning UV irradiation unit 16, the head moving mechanism 18, and the transport mechanism 84. Specifically, the control unit 22 performs the drawing operation by the inkjet head 14 to form the image portion on the printing original plate P, the reflected UV light from the scanning mirror 44 by the mirror moving mechanism 46 of the scanning UV irradiation unit 16. The main scanning of the inkjet head 14 by the scanning irradiation, the head moving mechanism 18 and the sub-scanning conveyance (preferably intermittent conveyance) of the scanning table 82 by the conveyance mechanism 84 are controlled.

In the example shown in FIGS. 6A and 6B, only the scanning UV irradiation unit 16 including the inkjet head 14, the head moving mechanism 18, and the UV lamp 40 is mounted on the scanning table 82. The invention is not limited to this, and in addition to these, any one of the irradiation unit moving mechanism 24 of the scanning UV irradiation unit 16 constituting the plate making apparatus 60 shown in FIG. One or both may be placed on the scanning table 82.
In this way, the scanning UV irradiation unit 16 placed on the scanning table 82 is moved in the sub-scanning direction with respect to the inkjet head 14 by the irradiation unit moving mechanism 24, so that the inkjet head 14 and the scanning UV are scanned. The distance L to the irradiation unit 16 can be adjusted.

Further, the transport mechanism 84 integrally moves the inkjet head 14 and the scanning UV irradiation unit 16 in the sub-scanning direction with respect to the printing original plate P, and adjusts the distance L by the irradiation unit moving mechanism 24. The distance L can be easily adjusted by moving the scanning UV irradiation unit 16 in the sub-scanning direction.
Furthermore, in addition to the inkjet head 14 and the scanning UV irradiation unit 16, the gum solution ejection head 26 and the head moving mechanism 28 are also integrated, so that not only the image part is properly formed on the printing original plate P but also the image. A gum solution film can be formed by selectively applying a gum solution for protecting the plate surface to a printing original plate or printing plate in which the portion is appropriately formed, and particularly preferably to a non-image portion.

Hereinafter, an example of the ink jet head 14 that can be suitably used in the ink jet drawing apparatus of the present invention and the plate making apparatus to which the ink jet drawing apparatus is applied will be described in detail with reference to FIGS.
FIG. 7 is a perspective view showing a schematic configuration of the appearance of the inkjet head 14, and FIG. 8 is a cross-sectional view showing a schematic configuration of the peripheral portion of one nozzle 14 a of the ink discharge head 14.

The inkjet head 14 has a plurality of nozzles 14a that eject ink droplets, and a recording electrode 14b and a piezoelectric element 14c are disposed in each nozzle 14a.
The nozzle 14a is made of an insulating material and has a cylindrical shape with an opening having a diameter of 200 μm or less at the tip. The nozzle 14a is filled with UV ink. A part of the ink filled in the nozzles 14a protrudes from the opening to form a hemispherical or cone-shaped meniscus. In addition, in this embodiment, although the nozzle was made into the column shape, this invention is not limited to this, It is good also as a rectangular parallelepiped shape.
Here, the opening of the nozzle 14a is preferably formed of a material having a high surface energy, such as Teflon (registered trademark). By forming the opening of the nozzle 14a with a material having a high surface energy, it is possible to prevent ink from spreading from the opening. By preventing the ink from spreading out, it is possible to prevent the meniscus shape from becoming unstable, remaining as dirt when the power is turned off, and adversely affecting subsequent recording.

Further, an ink chamber (not shown) for storing and replenishing ink Q is connected to the nozzle 14a. The UV ink chamber has pressurizing means (not shown), and the UV ink Q is supplied under pressure to the nozzles 14a by the pressurizing means. Here, the pressurizing means pressurizes and supplies the UV ink Q continuously or intermittently at an appropriate pressure to keep the shape of the meniscus 14d constant.
Furthermore, it is preferable to provide heating means in the UV ink chamber to maintain the temperature of the UV ink at a predetermined temperature.

The recording electrode 14b is disposed on the outer wall side of the tip portion of the nozzle 14a and is connected to a control unit (not shown). The control unit controls the voltage value and pulse width of the drive voltage applied to the recording electrode 14b when droplets are ejected and not ejected.
By applying a predetermined voltage corresponding to the first ejection signal from the control unit to the recording electrode 14b, droplets are ejected from the opening at the tip of the nozzle 14a.

Here, the recording electrode 14b may be arranged on either the inner wall side or the outer wall side of the nozzle 14a, but it is preferable to provide the recording electrode 14b on the outer wall side of the nozzle 14a as in the present embodiment. By providing the recording electrode 14b on the outer wall side of the nozzle 14a, it is possible to eliminate the influence of corrosion or the like due to contact with the UV ink.
Further, the distance from the tip of the nozzle 14a of the recording electrode 14b is not particularly limited. For example, in the present embodiment, when the position of the recording electrode 14b is separated from the tip of the nozzle 14a without changing the applied voltage, even when the recording electrode is disposed at a position separated by 10 cm or more from the tip of the nozzle 14a, A droplet can be suitably discharged.

The inkjet head 14 of this embodiment has the piezoelectric element 14c as a preferable aspect.
The piezoelectric element 14c is disposed on the outer wall surface upstream of the ink flow from the recording electrode of the nozzle 14a. The piezoelectric element 14c uses a piezo element or the like, and pressurizes the UV ink filled in the nozzle in synchronization with the voltage application to the recording electrode 14b. Thus, more stable recording can be performed by applying pressure using the piezoelectric element 14c.

  Here, in the present embodiment, the nozzle 14a is formed of an insulating material, and a predetermined voltage is applied to the recording electrode 14b in accordance with the first ejection signal. However, the present invention is not limited to this. Not. For example, when UV ink that can ignore corrosion and clogging due to contact is used as the UV ink, the nozzle is made of metal, and a droplet is formed by applying a signal voltage directly to the nozzle without providing a recording electrode. May be discharged.

The UV ink ejection operation by the inkjet head 14 will be described.
The nozzle 14a is pressurized and supplied with UV ink from the ink chamber, and a meniscus of UV ink is formed in the opening at the tip of the nozzle 14a.

In this state, when a predetermined voltage is applied to the recording electrode 14b according to the first ejection signal from the control unit, the meniscus vibrates (extends or contracts) from the tip of the nozzle 14a toward the printing original plate P, and printing is performed in an extended state. Dots are formed by adhering to the original P, or the tip of the meniscus is split, and the separated droplets fly in the direction of the original printing P and adhere to form dots.
In this way, the voltage applied to the recording electrode 14b is controlled in accordance with the first ejection signal, and UV ink dots are formed on the printing original plate P to form an image portion.
For the ink jet head, a method is also used in which the entire head is heated with a heater or the like to reduce the viscosity of the ink so that it can be easily discharged.

Next, the printing original plate suitably used for the plate making apparatus to which the ink jet drawing apparatus of the present invention is applied will be described.
A printing original plate that can be suitably used in a plate making apparatus to which the present invention is applied can be obtained by forming a specific ink-receiving layer on an appropriate support (base material). The (base material) is not particularly limited as long as it is a dimensionally stable plate having necessary strength and durability. For example, paper, plastic (for example, polyethylene, polypropylene, polystyrene, etc.) is laminated. Paper, metal plates (eg, aluminum, zinc, copper, etc.), plastic films (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene) , Polypropylene, polycarbonate, polyvinyl acetal, etc.), metal laminated Or vapor-deposited paper, or plastic films.

  Among them, in the present invention, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is at most 10% by mass. In the present invention, a support in which a sol-gel hydrophilic layer is provided on a surface-treated aluminum plate and polyester film is preferable. These are described below.

[Aluminum support]
Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements.
Thus, the composition of the aluminum plate applied to the present invention is not specified, and conventionally known and used aluminum plates can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, and particularly preferably 0.15 mm to 0.3 mm.

Such an aluminum plate may be subjected to surface treatment such as roughening treatment or anodizing treatment, if necessary. Hereinafter, such a surface treatment will be briefly described.
Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution for removing rolling oil on the surface is performed as desired. The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in JP-A-54-63902, a method in which both are combined can also be used.
The aluminum plate is further subjected to a hydrophilic treatment after being subjected to a surface treatment such as an anodizing treatment. Hydrophilic treatment includes silicate treatment and sol-gel treatment.

<Silicate processing>
A first aspect of the printing original plate that can be suitably used in the plate making apparatus of the present invention is characterized by having a silicate layer having a coating amount of 2.0 to 25 mg / m ² . This silicate layer is formed by a silicate process.
Hydrophilization treatment with an aqueous solution of an alkali metal silicate such as sodium silicate and potassium silicate is described in US Pat. No. 2,714,066 and US Pat. No. 3,181,461. It can be performed according to methods and procedures. Examples of the alkali metal silicate include sodium silicate, potassium silicate, and lithium silicate. The aqueous solution of alkali metal silicate may contain an appropriate amount of sodium hydroxide, potassium hydroxide, lithium hydroxide or the like. The aqueous solution of alkali metal silicate may contain an alkaline earth metal salt or a Group 4 (Group IVA) metal salt. Examples of the alkaline earth metal salt include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate; sulfates; hydrochlorides; phosphates; acetates; oxalates; Examples of the Group 4 (Group IVA) metal salt include titanium tetrachloride, titanium trichloride, potassium fluoride titanium, potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride. And zirconium tetrachloride. These alkaline earth metal salts and Group 4 (Group IVA) metal salts are used alone or in combination of two or more.

In the present invention, it is necessary to deposit 2.0 to 25 mg / m ² as the silicate deposition amount. Preferably it is 2.0-20.0 mg / m < ² >, and 5.0-15.0 mg / m < ² > is more desirable. When the silicate adhesion amount is 2.0 mg / m ² or more, ink bleeding is suppressed, and stains are less likely to occur. When the amount of silicate attached is 20.0 mg / m ² or less, the printing durability when a lithographic printing plate is obtained is preferable. In addition, even if the silicate adhesion amount exceeds 25 mg / m ² , further improvement in characteristics obtained by providing the silicate layer is not seen, which is disadvantageous in terms of cost. The silicate may exist as a continuous layer on the anode participating film, or may exist in an island shape.

The amount of silicate is measured as the amount of Si atoms (mg / m ² ) by a calibration curve method using a fluorescent X-ray analyzer, for example. More specifically, for example, the amount of Si atoms is measured from the peak height of the Si-Kα spectrum under the following conditions using RIX 3000 manufactured by Rigaku Corporation as a fluorescent X-ray analyzer under the following conditions. be able to.

Equipment: RIX3000 manufactured by Rigaku Denki Kogyo Co., Ltd.
X-ray tube: Rh
Measurement spectrum: Si-Kα
Tube voltage: 50 kV
Tube current: 50 mA
Slit: COARSE
Spectroscopic crystal: RX4
Detector: F-PC
Analysis area: 30mmφ
Peak position (2θ): 144.75 deg.
Background (2θ): 140.70 deg. 146.85 deg.
Integration time: 80 seconds / sample

<Sol-gel hydrophilic layer>
It is also preferable to provide a hydrophilic layer surface containing a sol-gel structure prior to forming the ink receiving layer, instead of the hydrophilic layer comprising the silicate layer.
That is, prior to forming the ink receiving layer on the support (base material), a sol-gel hydrophilic layer may be provided to produce a printing original plate. The support substrate is not particularly limited as long as it is a dimensionally stable plate having the required strength and durability. For example, paper, plastic (for example, polyethylene, polypropylene, polystyrene, etc.) is laminated. Paper, metal plates (eg, aluminum, zinc, copper, etc.), plastic films (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene) , Polypropylene, polycarbonate, polyvinyl acetal, etc.), papers laminated or vapor-deposited with metals as described above, or plastic films.

Hereinafter, the constitution of the sol-gel hydrophilic layer will be described.
<Hydrophilic binder>
In the present invention, the sol-gel hydrophilic layer contains a hydrophilic binder. The hydrophilic binder is preferably a sol-gel converting material composed of a metal hydroxide and a metal oxide, and among them, a sol-gel converting system having a property of forming a polysiloxane gel structure is most preferable.
The binder acts as a dispersion medium for the constituent components of the hydrophilic layer, improving the physical strength of the layer, improving the dispersibility between the components constituting the layer, improving the coatability, improving the printability, and making the plate. The configuration is suitable for various purposes such as convenience of sex.
The hydrophilic binder is preferably 30% by mass or more, and more preferably 35% by mass or more, based on the total solid content of the hydrophilic layer. If it is 30% by mass or less, the hydrophilic layer cannot obtain sufficient water resistance and abrasion resistance.

  As the hydrophilic polymer binder suitably used for the hydrophilic layer of the printing original plate, an organic polymer compound can be used for the purpose of imparting appropriate strength and surface hydrophilicity as the hydrophilic layer. Specifically, polyvinyl alcohol (PVA), modified PVA such as carboxy-modified PVA, starch and derivatives thereof, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, casein, gelatin, polyvinylpyrrolidone, vinyl acetate-crotonic acid Polymers, styrene-maleic acid copolymers, polyacrylic acid and salts thereof, polyacrylamides, water-soluble acrylic copolymers containing water-soluble acrylic monomers such as acrylic acid and acrylic amide as main constituents, etc. Water-soluble resin is mentioned.

  In addition, as a water-proofing agent that crosslinks and cures the organic polymer compound, initial condensates of aminoplasts such as glyoxal, melamine formaldehyde resin, urea formaldehyde resin, methylolated polyamide resin, polyamide / polyamine / epichlorohydrin adduct , Polyamide epichlorohydrin resin, modified polyamide polyimide resin, and the like. In addition, ammonium chloride, a crosslinking catalyst for a silane coupling agent, and the like can be used in combination.

The systems capable of sol-gel conversion that can be particularly preferably applied to the present invention are Sakuo Sakuo “Science of Sol-Gel Method”, Agne Jofusha (published) (1988), Satoshi Hirashima “Latest Sol-Gel Method” Is described in detail in books such as “Functional Thin Film Fabrication Technology” by the General Technology Center (published) (1992).
That is, the bonding group coming out of the polyvalent element forms a network structure through oxygen atoms, and at the same time, the polyvalent metal also has an unbonded hydroxyl group or an alkoxy group, resulting in a resinous structure in which these are mixed. The polymer is in a sol state at the stage where there are many alkoxy groups and hydroxyl groups before coating, and after coating, as the ester bond proceeds, the network-like resinous structure becomes stronger and gel state. become. Further, in addition to the property of changing the hydrophilicity of the resin structure, it also has a function of modifying the surface of the solid fine particles by bonding a part of the hydroxyl groups to the solid fine particles to change the hydrophilicity. The polyvalent binding element of the compound having a hydroxyl group or an alkoxy group that performs sol-gel conversion is aluminum, silicon, titanium, zirconium, etc., and any of these can be used in the present invention, but the following can be most preferably used A sol-gel conversion system using a siloxane bond will be described. Sol-gel conversion using aluminum, titanium, and zirconium can be performed by replacing silicon described below with each element.

  The hydrophilic matrix formed by sol-gel conversion is preferably a resin having a siloxane bond and a silanol group, and the hydrophilic layer of the direct-drawing lithographic printing original plate of the present invention is a silane compound having at least one silanol group The coating solution which is a sol system containing siloxane is formed by the progress of hydrolysis and condensation of silanol groups to form a siloxane skeleton structure and progress of gelation over time after coating. The siloxane resin forming the gel structure is represented by the following general formula (I), and the silane compound having at least one silanol group is represented by the following general formula (II). Moreover, the substance system contained in the hydrophilic layer that changes from hydrophilicity to hydrophobicity does not necessarily need to be a silane compound of the general formula (II) alone, and generally consists of an oligomer in which the silane compound is partially hydrolyzed. Alternatively, it may be a mixed composition of a silane compound and its oligomer.

The siloxane-based resin of the general formula (I) is formed by sol-gel conversion from a dispersion containing at least one silane compound represented by the following general formula (II), and R ⁰¹ in the general formula (I) At least one to R ⁰³ represents a hydroxyl group and the other represents an organic residue selected from R0 and Y ¹ symbols in the following general formula (II).

Formula (II) (R ⁰ ) _n Si (Y ¹ ) _4-n
In general formula (II), R ⁰ represents a hydroxyl group, a hydrocarbon group or a heterocyclic group. Y ¹ represents a hydrogen atom, a halogen atom, —OR ¹¹ , —OCOR ¹² , or —N (R ¹³ ) (R ¹⁴ ) (R ¹¹ and R ¹² each represents a hydrocarbon group, R ¹³ , R ¹⁴ may be the same or different and each represents a hydrogen atom or a hydrocarbon group). n represents 0, 1, 2 or 3.

As the hydrocarbon group or heterocyclic group represented by R ^{0 in} the general formula (II), a linear or branched alkyl group having 1 to 12 carbon atoms which may be substituted (for example, methyl group, ethyl group, propyl group) Group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, etc .; as a group substituted by these groups, a halogen atom (chlorine atom, fluorine atom, bromine atom) , Hydroxy group, thiol group, carboxy group, sulfo group, cyano group, epoxy group, —OR ¹ group (R ¹ is methyl group, ethyl group, propyl group, butyl group, heptyl group, hexyl group, octyl group, decyl group) Group, propenyl group, butenyl group, hexenyl group, octenyl group, 2-hydroxyethyl group, 3-chloropropyl group, 2-cyanoethyl group, N, N-dimethylaminoethyl , 2-bromoethyl group, 2- (2-methoxyethyl) oxyethyl group, 2-methoxycarbonylethyl group, 3-carboxypropyl group, a benzyl group, etc.), - OCOR ² group (R ² is and the R ¹ -COOR ² group, -COR ² group, -N (R ³ ) (R ³ ) (R ³ represents the same content as a hydrogen atom or R ^1, and each is the same or different. -NHCONHR ² group, -NHCOOR ² group, -Si (R ² ) ₃ group, -CONHR ³ group, -NHCOR ² group, etc. These substituents are substituted in plural in the alkyl group. A linear or branched alkenyl group having 2 to 12 carbon atoms which may be substituted (for example, vinyl group, propenyl group, butenyl group, pentenyl group, hexenyl group, octenyl group, decenyl group, Do Examples of the group substituted with these groups such as a senyl group include those having the same content as the group substituted with the alkyl group), and an optionally substituted aralkyl group having 7 to 14 carbon atoms (for example, , A benzyl group, a phenethyl group, a 3-phenylpropyl group, a naphthylmethyl group, a 2-naphthylethyl group, etc .; the groups substituted by these groups have the same contents as the groups substituted by the alkyl group An alicyclic group having 5 to 10 carbon atoms (for example, a cyclopentyl group, a cyclohexyl group, a 2-cyclohexylethyl group, a 2-cyclopentylethyl group, a norbornyl group). Examples of the group substituted by these groups such as an adamantyl group include those having the same contents as the substituents of the alkyl group, and may be substituted in plural), carbon An aryl group of 6 to 12 which may be substituted (for example, a phenyl group or a naphthyl group, and the substituent includes the same content as the group substituted with the alkyl group, or a plurality of substituted groups may be substituted. Or a heterocyclic group that may be condensed, containing at least one atom selected from a nitrogen atom, an oxygen atom, and a sulfur atom (for example, the heterocyclic ring includes a pyran ring, a furan ring, a thiophene ring, A morpholine ring, pyrrole ring, thiazole ring, oxazole ring, pyridine ring, piperidine ring, pyrrolidone ring, benzothiazole ring, benzoxazole ring, quinoline ring, tetrahydrofuran ring and the like may contain a substituent. Examples of the substituent include those having the same contents as the substituent in the alkyl group, and a plurality of substituents may be substituted.

As the —OR ¹¹ group, —OCOR ¹² group or N (R ¹³ ) (R ¹⁴ ) group of Y ^{1 in} the general formula (II), for example, the following groups are represented. In the —OR ¹¹ group, R ¹¹ is an optionally substituted aliphatic group having 1 to 10 carbon atoms (for example, methyl group, ethyl group, propyl group, butoxy group, heptyl group, hexyl group, pentyl group, octyl group, Nonyl group, decyl group, propenyl group, butenyl group, heptenyl group, hexenyl group, octenyl group, decenyl group, 2-hydroxyethyl group, 2-hydroxypropyl group, 2-methoxyethyl group, 2- (methoxyethyloxo) ethyl Group, 2- (N, N-diethylamino) ethyl group, 2-methoxypropyl group, 2-cyanoethyl group, 3-methyloxapropyl group, 2-chloroethyl group, cyclohexyl group, cyclopentyl group, cyclooctyl group, chlorocyclohexyl group , Methoxycyclohexyl group, benzyl group, phenethyl group, dimethoxybenzyl group, methyl A benzyl group, bromobenzyl group, and the like).

In the —OCOR ¹² group, R ¹² is an aliphatic group having the same content as R ¹¹ or an optionally substituted aromatic group having 6 to 12 carbon atoms (the aromatic group is exemplified by the aryl group in R above). The same as the above). In the —N (R ¹³ ) (R ¹⁴ ) group, R ¹³ and R ¹⁴ may be the same or different from each other, and each is a hydrogen atom or an aliphatic group having 1 to 10 carbon atoms which may be substituted (for example, And those having the same contents as R ¹¹ of the —OR ¹¹ group. More preferably, the total number of carbon atoms of R ¹¹ and R ¹² is 16 or less. Specific examples of the silane compound represented by the general formula (II) include the following.

Tetrachlorosilane, tetrabromosilane, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, methyltrichlorosilane, methyltribromosilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, Methyltri-t-butoxysilane, ethyltrichlorosilane, ethyltribromosilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, ethyltrit-butoxysilane, n-propyltrichlorosilane, n-propyltribromosilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltriisopropoxysilane, n-propyltrit-butoxysilane, n-hex Trichlorosilane, n-hexyltribromosilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-hexyltriisopropoxysilane, n-hexyltri-t-butoxysilane, n-decyltrichlorosilane, n-decyltribromosilane, n-decyltrimethoxysilane, n-decyltriethoxysilane, n-decyltriisopropoxysilane, n-decyltrit-butoxysilane, n-octadecyltrichlorosilane, n-octadecyltribromosilane, n-octadecyltrimethoxysilane, n-octadecyltriethoxysilane, n-octadecyltriisopropoxysilane, n-octadecyltri-t-butoxysilane, phenyltrichlorosilane, phenyltribromosilane, phenyltrimethoxy Silane, phenyltriethoxysilane, phenyltriisopropoxysilane, phenyltri-t-butoxysilane, dimethoxydiethoxysilane, dimethyldichlorosilane, dimethyldibromosilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldichlorosilane, diphenyl Dibromosilane, diphenyldimethoxysilane, diphenyldiethoxysilane, phenylmethyldichlorosilane, phenylmethyldibromosilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane, triethoxyhydrosilane, tribromohydrosilane, trimethoxyhydrosilane, isopropoxy Hydrosilane, tri-t-butoxyhydrosilane, vinyltrichlorosilane, vinyltribromosilane, vinyltrimethoxysila , Vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltrit-butoxysilane, trifluoropropyltrichlorosilane, trifluoropropyltribromosilane, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, trifluoropropyltri Isopropoxysilane, trifluoropropyltri-t-butoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane,

γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltriisopropoxysilane, γ-glycidoxypropyltri-t-butoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyl Diethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriisopropoxysilane, γ-methacryloxypropyltrit-butoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyl Diethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, γ-aminopropyltrit-butoxysilane, γ-mercaptopropylmethyldi Toxisilane, γ-mercaptopropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltriisopropoxysilane, γ-mercaptopropyltri-t-butoxysilane, β- (3 , 4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, and the like.

Along with the silane compound represented by the general formula (II) used for forming the hydrophilic layer according to the present invention, a metal compound that can be formed by bonding to a resin during sol-gel conversion of Ti, Zn, Sn, Zr, Al, etc. Can be used together. Examples of the metal compound used include Ti (OR ² ) ₄ (R ² is methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, etc.), TiCl ₄ , Zn (OR ² ) ₂ , Zn ( CH ₃ COCHCOCH ₃ ) ₂ , Sn (OR ² ) ₄ , Sn (CH ₃ COCHCOCH ₃ ) ₄ , Sn (OCOR ² ) ₄ , SnCl ₄ , Zr (OR ² ) ₄ , Zr (CH ₃ COCHCOCH ₃ ) ₄ , Al (OR ² ) _{3 and the} like.

  In addition, this gel structure matrix has a silane coupling group at the end of the polymer main chain for the purpose of improving physical properties such as film strength and flexibility, improving coating properties, and adjusting hydrophilicity. It is possible to add a hydrophilic polymer or a crosslinking agent.

  Examples of the hydrophilic polymer having a silane coupling group at the end of the polymer main chain include a polymer represented by the following general formula (1).

In the general formula (1), R ¹ , R ² , R ³ and R ⁴ each represent a hydrogen atom or a hydrocarbon group having 8 or less carbon atoms, m represents 0, 1 or 2, and n represents 1-8. An integer is represented, and p represents an integer of 30 to 300. Y represents —NHCOCH ₃ , —CONH ₂ , —CON (CH ₃ ) ₂ , —CONH ₃ , —OCH ₃ , —OH, —CO ₂ M or CONHC (CH ₃ ) ₂ SO ₃ M, and M represents a hydrogen atom. Represents any one selected from the group consisting of alkali metal, alkaline earth metal and onium.

  L represents a single bond or an organic linking group, wherein the organic linking group represents a polyvalent linking group composed of a nonmetallic atom, specifically 1 to 60 carbon atoms, 0 to 10 carbon atoms. A nitrogen atom, 0 to 50 oxygen atoms, 1 to 100 hydrogen atoms, and 0 to 20 sulfur atoms. More specific examples of the linking group include the following structural units or groups formed by combining them.

  Specific examples of the hydrophilic polymer having a silane coupling group of the general formula (1) include the following polymers. In the specific examples below, p can be any value between 100 and 250.

  The hydrophilic polymer according to the present invention includes a radical polymerizable monomer represented by the following general formula (2), and a silane coupling agent having chain transfer ability in the radical polymerization represented by the following general formula (3): And can be synthesized by radical polymerization. Since the silane coupling agent, Formula (3), has chain transfer ability, it is possible to synthesize a polymer in which a silane coupling group is introduced at the end of the polymer main chain in radical polymerization.

  As described above, it is particularly preferable to provide a hydrophilic layer produced by a sol-gel method between the ink receiving layer and the support.

<Inorganic fine particles>
Furthermore, the hydrophilic layer containing a sol-gel structure may contain inorganic fine particles for improving the strength of the cured film in the image area and improving the on-press developability of the non-image area.
As the inorganic fine particles, for example, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate or a mixture thereof can be preferably mentioned. Even if they are not photothermally convertible, they can be used for strengthening the film, enhancing interfacial adhesion by surface roughening, and the like.
The inorganic fine particles preferably have an average particle size of 5 nm to 10 μm, and more preferably 0.5 to 3 μm. Within the above range, it is possible to form a non-image portion excellent in hydrophilicity that is stably dispersed in the hydrophilic layer, sufficiently retains the film strength, and hardly causes stains during printing.
The inorganic fine particles as described above can be easily obtained as a commercial product such as a colloidal silica dispersion.
The content of the inorganic fine particles is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total solid content of the hydrophilic layer.

<Formation of sol-gel hydrophilic layer>
The sol-gel hydrophilic layer is coated by preparing a coating solution by dispersing or dissolving the necessary components in a solvent. Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, toluene, water, and the like. However, the present invention is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.
The sol-gel hydrophilic layer according to the present invention can be formed by preparing a plurality of coating solutions in which the same or different components are dispersed or dissolved in the same or different solvents, and repeatedly applying and drying a plurality of times. .

A sol-gel hydrophilic layer can be formed by applying the hydrophilic coating solution composition prepared as described above to the support surface and drying. The film thickness of the sol-gel hydrophilic layer can be selected depending on the purpose, but is generally in the range of 0.5 to 5.0 g / m ² , preferably 1.0 to 3.0 g / m ² after drying. The range is m ² . If the coating amount is less than 0.5 g / m ^2, it is difficult to achieve a hydrophilic effect, and if it exceeds 5.0 g / m ² , the film strength tends to be lowered.

<Ink receiving layer>
As described above, it is preferable to provide an ink receiving layer on the surface of the hydrophilic layer selected from the silicate layer or the sol-gel hydrophilic layer as the printing original plate that can be suitably used in the plate making apparatus of the present invention. The ink receiving layer is a layer containing 1.0 to 50.0 mg / m ² of an organic fluorine compound having 5 or more fluorine atoms per molecule, or an organic material having 5 or more fluorine atoms per molecule. a fluorine compound and 1.0 to 50 mg / m ^2, a hydrophilic resin and 1.0 to 50.0 mg / m ^2, a layer containing a.
These ink receiving layers are provided on the surface of a hydrophilic layer comprising a silicate layer or a hydrophilic layer containing a sol-gel structure, which is provided in advance on a support.

The printing original plate is preferably provided with an ink receiving layer on a silicate layer provided by silicate treatment on the surface of an anodized film formed on an aluminum substrate, or on a sol-gel hydrophilic layer. As the ink receiving layer component, an organic fluorine compound having 5 or more fluorine atoms is preferably provided in a range of 50 mg / m ² or less. By making the content of the organic fluorine compound in the range of 1.0 to 50.0 mg / m ² , it is possible to achieve both excellent adhesion with the image area and surface hydrophilicity when producing a lithographic printing plate. The non-image area is difficult to stain and high printing durability is achieved.
[Organic fluorine compounds having 5 or more fluorine atoms]
As the ink receiving layer component, the organic fluorine compound preferably has 5 or more fluorine atoms per molecule or, in the case of a polymer compound, 5 or more per structural unit. By setting the number to 5 or more, an ink bleeding suppression effect can be suitably obtained. The organic fluorine compound is preferably water-soluble, and a compound having a surface active action is preferred.
A preferred fluorine-based compound according to the present invention is represented by the general formula R _F -Rpol. In the formula, R _F represents a linear or branched perfluoroalkyl group having 3 or more carbon atoms, Rpol represents carboxylic acid or a salt thereof, sulfonic acid or a salt thereof, phosphoric acid or a salt thereof, phosphonic acid or a salt thereof, An amino group or a salt thereof, a quaternary ammonium salt, a polyethyleneoxy skeleton, a polypropyleneoxy skeleton, a sulfonamide group, an ether group, a polar group such as a betaine structure. Of these, those having a structure of a sulfoxyl group or a salt thereof are more preferable because they hardly interact with the silicate and are developed on the machine. Further, R _F is particularly preferably one having a C _n F _{2n + 1} C _m H _2m COO-skeleton from the viewpoint of suppressing ink bleeding, and two or more C _n F _{2n + 1} C _m H _{2m in} one molecule. Those having a COO-skeleton are more preferred. Here, n is an integer of 2 or more, and m is an integer of 1 or more.
Specific examples [(F-1) to (F-19)] of fluorine-based compounds preferably used in the present invention are listed below, but the present invention is not limited thereto.

Moreover, you may use a high molecular fluorine-type compound as a fluorine-type compound which concerns on this invention. In particular, those having a surfactant action and water-soluble are preferred.
Specific examples of the polymeric fluorosurfactant include a copolymer of an acrylate having a fluoroaliphatic group or a methacrylate having a fluoroaliphatic group and a poly (oxyalkylene) acrylate or poly (oxyalkylene) methacrylate. It is done. In the copolymer, the monomer unit of acrylate or methacrylate having a fluoroaliphatic group is preferably 7 to 60% by mass based on the mass of the copolymer, and the molecular weight of the copolymer is 3000 to 100,000. Is appropriate.

  The fluoroaliphatic group has 3 to 20 carbon atoms, may be linear or branched, contains 40% by mass or more of fluorine, and has at least three terminal carbon atoms sufficiently A fluorinated fluoroaliphatic group is preferred. Specific examples of the acrylate or methacrylate having the fluoroaliphatic group include N-butylperfluorooctanesulfonamidoethyl acrylate, N-propylperfluorooctanesulfonamidoethyl acrylate, and methylperfluorooctanesulfonamidoethyl acrylate. The molecular weight of the polyoxyalkylene group in the poly (oxyalkylene) acrylate or methacrylate is preferably 200 to 3000. Examples of the oxyalkylene group include oxyethylene, oxypropylene, and oxybutylene groups, preferably oxyethylene and oxypropylene groups. For example, acrylate or methacrylate having 8 to 15 moles of oxyethylene group added is used. Moreover, foamability can be suppressed by adding a dimethylsiloxane group etc. to the terminal of this polyoxyalkylene group as needed.

The fluorosurfactants as described above can be generally obtained on the market, and in the present invention, commercially available products can be used. Two or more fluorosurfactants can be used in combination.
As products sold, Surflon S-111, S-112, S-113, S-121, S-131, S-141, S-145, S-381, S-382, manufactured by Asahi Glass Co., Ltd. Dainippon Ink & Chemicals, Inc. MegaFuck F-110, F120, F-142D, F-150, F-171, F177, F781, Sumitomo 3M Fluorad FC-93, FC-95, FC- 98, FC-129, FC135, FX-161, FC170C, FC-171, FC176, Bayer Japan KK-made FT-248, FT-448, FT-548, FT-624, FT-718, FT-738, etc. Is mentioned.

-Combination with hydrophilic resin-
These organic fluorine compounds and hydrophilic resins can be blended to form an ink receiving layer. By using in combination with a hydrophilic resin, it is possible to further improve resistance to smearing and suppression of ink bleeding. The organic fluorine compound in this case is 1.0 to 50 mg / m ^2, preferably 2.0
In the range of to 10 mg / m ^2, the hydrophilic resin is 1.0 to 50 mg / m ^2, preferably in the range of 2.0~20.0mg / m ^2. By using a hydrophilic resin in combination, the ink repellency of the non-image area is further improved.
As the hydrophilic resin, there is no problem as long as it is a water-soluble resin, but in particular, a water-soluble cellulose (for example, carboxymethyl cellulose) having a carboxylic acid or a salt thereof, an acrylic or methacrylic polymer or a copolymer thereof, a sulfonic acid group or a salt thereof. Acrylic, methacrylic, vinyl, styrenic hydrophilic resins having amide groups, hydrophilic resins containing amide groups such as polyacrylamide or polyvinylpyrrolidone, hydrophilic resins having amino groups, hydrophilic resins having phosphoric acid or salts thereof, for example Examples thereof also include phosphate-modified starch described in Japanese Utility Model Publication No. 62-097892.

It is also preferable to contain a compound having an onium group. The compounds having an onium group are described in detail in JP-A Nos. 2000-10292 and 2000-108538. In addition, a compound selected from the group of polymer compounds having a structural unit represented by poly (p-vinylbenzoic acid) in the molecule can also be used. Specific examples of these polymer compounds include a copolymer of p-vinylbenzoic acid and vinylbenzyltriethylammonium salt, a copolymer of p-vinylbenzoic acid and vinylbenzyltrimethylammonium chloride, and the like. .
A copolymer having a repeating unit containing at least one ethylenically unsaturated bond and a repeating unit containing at least one functional group that interacts with the support surface described in JP-A-2005-125749 is also preferable.
Among these, a polymer having a sulfonate skeleton is particularly preferable in terms of suppressing ink bleeding and making it difficult to stain.

This organic ink receiving layer can be provided by the following method. That is, a method in which water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof is dissolved and applied on an aluminum plate and dried, and water, methanol, ethanol, methyl ethyl ketone, etc. In this method, an aluminum plate is immersed in a solution obtained by dissolving the organic compound in an organic solvent or a mixed solvent thereof to adsorb the compound, and then washed with water and dried to provide an organic undercoat layer. . In the former method, a solution having a concentration of 0.005 to 10% by mass of the organic compound can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The former application method is preferable because it does not adsorb to the substrate and is less likely to get dirty during printing.
From the viewpoint of suppressing smudges during printing, when the contact angle of water to the substrate (0.8 μl of water is slowly dropped onto the substrate in the air and the contact angle after 10 seconds is measured) is 8 ° or less, printing Dirt is suppressed.

  Next, the UV ink that can be suitably used in the present invention will be described.

The UV ink used in the present invention has an ink viscosity in the range of 1 to 1000 mPa · s and a surface tension in the range of 1 to 100 mN / m at the temperature at the time of ejection from the viewpoint of ejection properties. It is preferable that it exists in. Furthermore, it is preferable that the viscosity of the ink is in the range of 1 to 100 mPa · s and the surface tension is in the range of 1 to 80 mN / m at the temperature at the time of ejection.
Also, from the viewpoint of suppressing ink bleeding, the combination of the printing original plate and UV ink is based on the contact angle of UV ink to the printing original plate (0.8 μl of ink is slowly dropped on the substrate in the air, and the contact angle after 10 seconds is set. (Measurement) is preferably 30 ° or more. Thereby, ink bleeding is suppressed.

  The UV ink (ultraviolet curable ink) suitably used in the present invention can be obtained by a known method described in “Latest UV Curing Practical Handbook” (published on February 25, 2005) issued by the Technical Information Association. It can be prepared and contains a polymerization initiator, a polymerizable monomer or an oligomer as a main component. There are two types of polymerization, radical polymerization type and ion polymerization type such as cationic polymerization, both of which can be suitably used in the present invention.

  Examples of the polymerization initiator that can be suitably used in the present invention include known radical polymerization or cationic polymerization photopolymerization initiators used for ultraviolet curable ink compositions. The other photopolymerization initiator that can be used in combination with the present invention causes a chemical change through the action of light or interaction with the electronically excited state of the sensitizing dye, and is at least one of a radical, an acid, and a base. A compound that produces one species. As the specific photopolymerization initiator, those known to those skilled in the art can be used without limitation. Preferred photopolymerization initiators include aromatic ketones, benzoin derivatives such as benzoin and benzoin ether, onium salts such as sulfonium salts and iodonium salts, organic peroxides, hexaarylbiimidazole compounds, ketoxime esters, and borate salts. , Azinium compounds, metallocene compounds, compounds having a carbon-halogen bond, and the like. These compounds have a polymerization initiating ability with respect to ultraviolet rays, but may be spectrally sensitized to visible light and infrared rays in combination with an appropriate sensitizer.

  In the present invention, examples of the polymerizable monomer or oligomer suitably used include known radical polymerizable or cationic polymerizable monomers or oligomers. Monomers or oligomers used include (meth) acrylates, (meth) acrylamides, (meth) acrylic acid, maleic acid and derivatives thereof, styrenes, olefins, vinyl ethers, vinyl esters, epoxy compounds, oxetane compounds And cyclic esters. In order to control the mechanical properties of the formed image, in the present invention, these compounds can be used in combination with a monofunctional compound having one polymerizable functional group in the molecule and a polyfunctional compound having two or more.

  In addition, the ink is preferably colored for the visibility of the image. A known dye or pigment can be used for coloring. In addition, a surfactant for improving ejection properties, a polymerization inhibitor for stability during storage of ink, and the like can be added. Furthermore, various polymers can be added to improve the mechanical properties of the formed image. Specifically, (meth) acrylic polymer, polyurethane resin, polyamide resin, polyester resin, epoxy resin, phenol resin, polycarbonate resin, polyvinyl butyral resin, polyvinyl formal resin, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, polypropylene glycol, Shellac resins, vinyl resins, rubber resins, waxes, and other natural resins can be used.

  In the present invention, ink containing no solvent may be used as described above, but water or an organic solvent may be mixed. Examples of organic solvents to be mixed include ketone solvents such as acetone and methyl ethyl ketone, methanol, ethanol, propanol, 1-methoxy-2-propanol, ethylene glycol, diethylene glycol, dipropylene glycol, diethylene glycol monoethyl ether, tripropylene glycol, and tripropylene. Alcohol solvents such as glycol monomethyl ether, aromatic solvents such as toluene, ester solvents such as ethyl acetate, butyl acetate, isopropyl acetate and γ-butyrolactone, ether solvents such as tetrahydrofuran and diethylene glycol diethyl ether, Isopar G (Exxon) And hydrocarbon solvents such as

  Next, an example of a gum solution suitably used for the plate making apparatus of the present invention will be specifically described.

  As the gum solution, a desensitizing solution used for desensitizing a lithographic printing plate having an aluminum plate as a support can be used effectively. Preferable desensitizing liquid includes an aqueous solution containing at least one of a hydrophilic organic polymer compound, hexametaphosphoric acid and a salt thereof, phytic acid and a salt thereof.

  Specific hydrophilic organic polymer compounds include gum arabic, dextrin, alginates such as sodium alginate, water soluble cellulose such as carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide. , Water-soluble copolymers containing acrylamide units, polyacrylic acid, copolymers containing acrylic acid units, polyacrylic acid, copolymers containing acrylic acid units, polymethacrylic acid, copolymers containing methacrylic acid units, Examples thereof include a copolymer of vinyl methyl ether and maleic anhydride, a copolymer of vinyl acetate and maleic anhydride, and phosphoric acid-modified starch. Among them, gum arabic is preferable because of its strong desensitizing action. These hydrophilic polymer compounds can be used in combination of two or more as required, and are used at a concentration of about 1 to 40% by weight, more preferably 3 to 30% by weight.

  Specific examples of the hexametaphosphate include alkali metal hexametaphosphate and ammonium salt. Examples of the alkali metal salt or ammonium salt of hexametaphosphate include sodium hexametaphosphate, potassium hexametaphosphate, ammonium hexametaphosphate and the like. Specific examples of phytic acid or salts thereof include alkali metal salts such as sodium salt, potassium salt and lithium salt, ammonium salt and amine salt. Examples of amine salts include diethylamine, triethylamine, n-propylamine, di-n-propylamine, tri-n-propylamine, n-butylamine, n-amylamine, n-hexylamine, laurylamine, ethylenediamine, trimethylenediamine, Mention may be made of salts of tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, ethanolamine, diethanolamine, triethanolamine, allylamine, aniline and the like. The phytate may be a normal salt in which all 12 hydrogens of the acid are replaced, a hydrogen salt in which a part of the hydrogen of the acid is replaced (acidic salt), or a simple salt composed of a single base salt, 2 Any form of a double salt containing at least one kind of base as a component can be used. These compounds can be used alone or in combination of two or more.

  The desensitizing liquid used in the present invention preferably further contains a metal salt of a strong acid, whereby the desensitizing action can be enhanced. Specific metal salts of strong acids include sodium salt of potassium, potassium salt, magnesium salt, calcium salt and zinc salt, sodium salt of sulfuric acid, potassium salt, magnesium salt, calcium salt and zinc salt, sodium salt of chromic acid, Examples thereof include potassium salts, magnesium salts, calcium salts and zinc salts, and sodium fluoride and potassium fluoride. These metal salts of strong acids can be used in combination of two or more, and the amount is preferably about 0.01 to 5% by weight based on the total weight of the desensitizing solution. The desensitizing liquid used in the present invention has a pH value adjusted to an acidic range, more preferably 1 to 5, and most preferably 1.5 to 4.5. Therefore, when the pH of the aqueous phase is not acidic, more acid is added to the aqueous phase. Examples of the acid added as the pH adjuster include mineral acids such as phosphoric acid, sulfuric acid and nitric acid, such as citric acid, succinic acid, malic acid, glacial acetic acid, lactic acid, succinic acid, p-toluenesulfonic acid, and organic phosphonic acid. Examples thereof include organic acids. Of these, phosphoric acid not only functions as a pH adjuster, but also has an effect of enhancing the desensitizing effect, and is particularly excellent, 0.01 to 20% by weight based on the total weight of the desensitizing solution, Most preferably, it is contained in the range of 0.1 to 10% by weight.

  The desensitizing liquid used in the present invention preferably contains a wetting agent and / or a surfactant, whereby the applicability of the desensitizing liquid can be improved. Specific examples of the wetting agent include lower polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol, pentanediol, hexylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, and tripropylene. Glycol, glycerin, sorbitol, pentaerythritol and the like can be mentioned, and particularly preferred is glycerin. Examples of the surfactant include nonionic surfactants such as polyoxyethylene alkylphenyl ether and polyoxyethylene polyoxypropylene block copolymer, such as fatty acid salts, alkyl sulfate hydrochloride, alkylbenzene sulfonates, alkyl naphthalene sulfonates. Anionic surfactants such as dialkylsulfosuccinic acid ester salts, alkylphosphoric acid ester salts, and naphthalenesulfonic acid formalin condensates, for example, amphoteric surfactants of betaine type, glycine type, alanine type, and sulfobetaine type can be used. These wetting agents and / or surfactants are contained in the range of about 0.5 to 10% by weight, more preferably 1 to 5% by weight, based on the total weight of the desensitizing solution. The desensitizing liquid used in the present invention may further contain a filler such as silicon dioxide, talc and clay in an amount of up to 2% by weight and a dye or pigment in an amount of up to 1% by weight. it can.

The desensitizing solution used in the present invention is composed of the hydrophilic aqueous solution as described above, but is described in each specification such as U.S. Pat. Nos. 4,253,999, 4,268,613, and 4,348,954. It is also possible to use an emulsifying type desensitizing liquid. The coating amount of the desensitizing solution is 0.001 to 50 g / m ² , preferably 0.01 to 10 g / m ² in terms of dry weight.

  As mentioned above, although the inkjet drawing method and apparatus of this invention were demonstrated in detail, this invention is not limited to the said embodiment, In the range which does not deviate from the main point of this invention, it is possible to perform various improvement and a change. Of course.

  For example, in this embodiment, UV ink is used as the ink, but the present invention is not limited to this, and various photocurable inks that can use visible light and infrared light as curing light can also be used. Similarly, various active light sources that emit active light such as visible light can be used as the light source.

  In the above embodiment, the present invention is described in detail by giving an example in which the present invention is applied to a plate making apparatus using a printing original plate as an image recording medium. However, the present invention is not limited to this, and various drawing apparatuses, Of course, it may be applied to an image recording apparatus.

1 is a schematic top view showing a schematic configuration of an embodiment of a plate making apparatus to which an ink jet drawing apparatus according to the present invention is applied. It is typical sectional drawing of the plate-making apparatus shown in FIG. (A) And (b) is a typical sectional view and a typical fragmentary sectional view of a scanning type ultraviolet irradiation part of a plate making device shown in Drawing 1, respectively. It is a typical top view which shows schematic structure of other embodiment of the plate-making apparatus to which the inkjet drawing apparatus which concerns on this invention is applied. FIG. 5 is a schematic cross-sectional view of a scanning ultraviolet irradiation unit and an irradiation unit moving mechanism of the plate making apparatus shown in FIG. 4. (A) is a typical top view which shows schematic structure of other embodiment of the plate-making apparatus to which the inkjet drawing apparatus which concerns on this invention is applied, (b) is schematic structure of the plate-making apparatus shown to (a). It is a typical sectional view shown. It is a perspective view which shows schematic structure of the external appearance of one Embodiment of the inkjet head used for the plate-making apparatus shown in FIG. It is sectional drawing which shows schematic structure of the peripheral part of the nozzle of the inkjet head shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 60, 80 Plate making apparatus 12 Support stand 14 Inkjet head 16 Scanning ultraviolet (UV) irradiation part 18, 28 Head movement mechanism 20, 84 Conveyance mechanism 22 Control part 24 Irradiation part movement mechanism 26 Gum liquid discharge head 30 Feed roller 32 Retaining roller 34, 66a, 66b, 72, 90 Drive screw 35, 67a, 67b, 73, 88a, 88b Guide rail 36a, 68a, 70a, 74a Drive support part 36b, 68b, 70b, 74b Support part 40 Ultraviolet (UV) Lamp 42 Reflector 44 Scanning mirror 46 Mirror moving mechanism 48a, 48b Conveying roller 50 Endless belt 50a, 50b Belt portion 52 Drive source (motor)
54 Illumination window 56a, 56b Mirror plate 62a, 62b, 63a, 63b, 92a, 92b Support leg 64a, 64b Support member 64b
82 Scanning table 82a, 82b Opening 86a, 86b Base 94a, 94b Wheel 96 Traveling nut

Claims (14)

An inkjet drawing apparatus for recording an image on a sheet-like image recording medium by an inkjet recording method,
A support for supporting the image recording medium;
An inkjet head that is disposed to face the support table and ejects photocurable ink as ink droplets in an image-like manner on the image recording medium placed on the support table;
A head moving mechanism for moving the inkjet head in the main scanning direction;
Opposite to the support table, the image recording medium is disposed downstream of the inkjet head so as to be separated from the ink jet head by a predetermined distance, and the image recording medium is irradiated with actinic rays scanned in the main scanning direction. A scanning active light irradiation unit for curing the photocurable ink ejected on the image recording medium;
A transport mechanism that transports the image recording medium relative to the inkjet head in a sub-scanning direction substantially orthogonal to the main scanning direction;
The scanning active light irradiation unit is
A point-like or substantially point-like active light source that emits the active light; and
Parallel light generating means for generating the active light emitted from the active light source as parallel light parallel to the recording surface of the image recording medium supported by the support;
A scanning mirror that reflects the parallel light generated by the parallel light generation means to the image recording medium side and is movable in the main scanning direction;
An ink jet drawing apparatus having a mirror moving mechanism for moving the scanning mirror in the main scanning direction. The mirror moving mechanism is
Two transport rollers disposed on both outer sides of the image recording medium in the main scanning direction;
An endless belt that is stretched between these two conveying rollers and attached with the scanning mirror inclined at a predetermined angle;
The belt portion on the image recording medium side of the endless belt has an irradiation window formed adjacent to the mounting position of the scanning mirror and transmitting the irradiation light reflected by the scanning mirror. Inkjet drawing device. The scanning-type actinic light irradiation unit further includes two specular plates disposed on both sides of the endless belt in the sub-scanning direction and having inner portions facing each other as mirror surfaces,
The parallel light generation means includes a reflector having an emission port of the rectangular cross section that emits the active light emitted from the active light source as the parallel light of a rectangular cross section,
The active light source and the reflector are arranged between two parallel belt portions of the endless belt and outside the main scanning direction of the image recording medium,
The inner portions of the two endless belts parallel to each other facing each other form a mirror surface,
The scanning mirror is attached to the inside of the belt portion on the support side of the two belt portions so as to be inclined at the predetermined angle,
The irradiation window is formed at a position where the irradiation light reflected by the scanning mirror is transmitted through the belt part on the support side.
Between the two parallel belt portions of the endless belt and between the two mirror plates, a rectangular cross-sectional waveguide that guides the parallel light of the rectangular cross-section emitted from the exit of the reflector is formed. The inkjet drawing apparatus according to claim 2.   The inkjet drawing apparatus according to claim 3, wherein the endless belt is a stainless steel belt in which inner portions of the two belt portions facing each other are mirror surfaces. Further, an irradiation unit moving mechanism that moves the scanning type active light irradiation unit relative to the inkjet head in the sub-scanning direction;
The control unit that controls the irradiation unit moving mechanism or the head moving mechanism and the irradiation unit moving mechanism so that the scanning active light irradiation unit and the inkjet head are separated from each other by the predetermined distance or more. The inkjet drawing apparatus in any one of -4.   The inkjet drawing apparatus according to claim 1, wherein the transport mechanism is a mechanism that transports the image recording medium in the sub-scanning direction.   The inkjet according to any one of claims 1 to 5, wherein the transport mechanism is a mechanism that mounts the inkjet head, the head moving mechanism, and the scanning-type actinic light irradiation unit and moves them integrally in the sub-scanning direction. Drawing device.   The inkjet drawing apparatus according to claim 1, wherein the predetermined distance is a distance at which an influence of heat by the active light source does not affect drawing by the inkjet head.   The predetermined distance includes the drawing speed by the ink jet head, the type or structure of the ink jet head and the active light source, the transport speed of the image recording medium relative to the ink jet head in the sub-scanning direction, and the image recording medium. The inkjet drawing apparatus according to any one of claims 1 to 8, which is determined in accordance with at least one of the material or the material and the amount of active light emitted from the active light source. The inkjet drawing apparatus according to claim 1, wherein the image recording medium is a lithographic printing plate. The image recording medium is a lithographic printing original plate,
Furthermore, the inkjet drawing apparatus in any one of Claims 1-10 which has a plate surface protection liquid discharge head which discharges a plate surface protection liquid on the said printing original plate drawn by the said inkjet head. Inkjet recording that directly forms an image on a sheet-like image recording medium that is relatively conveyed in a sub-scanning direction orthogonal to the main-scanning direction using a photocurable ink by a serial-type inkjet head that moves in the main-scanning direction A method,
The photocurable ink is ejected in an image-like manner as ink droplets by the ink jet head and directly drawn,
The active light from a stationary point-like or substantially point-like active light source is scanned in the main scanning direction at a rear position spaced a predetermined distance from the drawing position by the inkjet head to the downstream side of the image recording medium in the sub-scanning direction. Irradiation on the image recording medium by a moving scanning mirror,
An inkjet drawing method comprising: curing the photocurable ink ejected imagewise on the image recording medium to form the image.   The inkjet drawing method according to claim 12, wherein the predetermined distance is a distance at which an influence of heat from the active light source does not affect drawing by the inkjet head.   The predetermined distance includes the drawing speed by the ink jet head, the type or structure of the ink jet head and the active light source, the transport speed of the image recording medium relative to the ink jet head in the sub-scanning direction, and the image recording medium. The inkjet drawing method according to claim 12 or 13, wherein the ink-jet drawing method is determined according to at least one of the above-described material or the material and the amount of active light emitted from the active light source.

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